It’s not a simple question and research is still moving, but here are 5 things to know.

1. The number on the scale is not the whole story.

When you lose weight quickly, a meaningful portion of what you lose is muscle, not just fat.

Here’s why it matters: a study published this year in JAMA Network Open followed 5,472 women over 8.3 years and found that women with the highest grip strength had a 33% lower risk of dying from any cause compared to women with the lowest, and that held even for women who weren’t exercising regularly (LaMonte et al., 2026). For reference, grip strength acts as a proxy for total muscle.

This muscle loss doesn’t register on the scale. It shows up later as strength that doesn’t come back, energy that stays low, and function that quietly declines. For a woman in midlife who is already losing muscle at the rate that age guarantees, that’s a risk worth understanding before she starts.

2. These medications tend to make you move less, not more.

Most people assume losing weight will make them feel better and naturally become more active. A study presented at ENDO 2026 found the opposite: after starting a GLP-1, daily step counts dropped from 5,047 to 4,487 steps per day, and moderate-to-vigorous activity fell from 28 to 22 minutes per day (Maharjan et al., ENDO 2026).

This is the first large study analyzing wearable device data in GLP-1 users, and the finding matters. The appetite suppression that makes these medications effective may also suppress the energy and drive that motivates movement.

What’s clear is that waiting for motivation to show up on its own is not a plan. Movement needs to be built in from the start.

3. Protein is the first thing to disappear when appetite drops.

Most women starting a GLP-1 don’t have a daily protein target in mind. Most aren’t hitting one.

The research on active women puts the minimum for protecting muscle during weight loss at 1.6 grams of protein per kilogram of body weight per day, spread across meals rather than eaten all at once (Wohlgemuth et al., 2021, JISSN; Smith-Ryan et al., 2022, Sports Medicine). For a 150-pound woman, that’s 109 grams daily. When eating feels like effort, that number doesn’t happen by accident.

My lab data adds something directly useful here. In a randomized trial in women, eating protein before exercise increased post-exercise resting metabolism and fat burning significantly more than eating carbohydrate did (Wingfield, Smith-Ryan et al., Sports Medicine - Open, 2016). The very mechanism that makes GLP-1 effective, reduced hunger and slower digestion, works against the nutritional conditions that protect muscle during weight loss. Knowing that upfront changes what you plan for.

4. Lifting weights is the signal your body needs to keep muscle.

Protein gives your body the raw material to maintain muscle. Resistance training gives it a reason to. Without that signal, even a solid protein intake won’t fully protect lean mass during aggressive weight loss.

I co-authored the 2026 ACSM Position Stand on resistance training, which showed two training sessions per week, with progressive overload, is enough to produce meaningful improvements in muscle strength and function across ages and starting fitness levels (Currier, Smith-Ryan et al., 2026). That’s a low bar by design.

5. Supplements fill real gaps when you’re barely eating.

Essential amino acids (EAAs). When eating enough protein feels like too much, EAAs are the most direct way to keep the muscle-building signal running. 6 to 12 grams with adequate leucine (the amino acid that directly switches on muscle protein synthesis) produces a protective effect comparable to a full meal’s worth of protein. Take them around training for the most benefit (Wohlgemuth et al., 2021).

Omega-3 fatty acids (EPA + DHA). On top of cardiovascular and anti-inflammatory effects, omega-3s increase muscle protein synthesis and reduce muscle loss during periods of restricted eating. 1 to 3 grams daily from fish oil is the practical range backed by evidence (Smith et al., 2011, Clinical Science; Wohlgemuth et al., 2021). GLP-1-related hair thinning is a reported concern for a lot of women; omega-3s tend to help there too.

Vitamin D3. Deficiency directly affects muscle strength, and the connection to bone density gets harder to reverse the longer it goes unaddressed. 2,000 IU daily, taken with a fat-containing meal because it’s fat-soluble, is the evidence-supported starting point (Smith-Ryan et al., 2022).

Magnesium. If sleep has gotten worse since starting a GLP-1, this is the first one to address. It’s also involved in protein synthesis and energy metabolism, and its importance for women increases during the menopause transition. 310 to 320 milligrams daily is baseline (Smith-Ryan et al., 2022).

Things to do right now:

Get a baseline body composition measure before you start. A smart scale that tracks fat mass and muscle mass separately isn’t clinical-grade, but consistent readings at the same time each morning give you something real to track. If you have access to DXA or InBody, use it. The scale alone won’t tell you what you’re actually losing.

Audit your diet before appetite disappears. Spend a week noticing what you’re actually eating. Where does your protein come from? What do you default to when you’re tired or rushed? Those defaults are the ones that still need to work when eating feels like effort.

Build your movement routine before you need the motivation. Two resistance training sessions per week, plus daily steps as a floor. Intensity matters less than the habit existing at all.

GLP-1 medications work. Going in without a plan has costs that don’t show up right away. Protein and movement aren’t things you layer on once the weight is gone. They’re the foundation that determines what you’re left with when it is.

Next up: I’ll share exactly what’s in my own supplement cabinet right now.

I have eaten this dinner. I have enjoyed this dinner.

The problem isn’t girl dinner; it’s the assumptions it comes with: smaller, lighter, less food. For active women being asked to train and perform (even for life), that assumption has measurable costs.

And to be clear, after decades of absorbing the eat-less message, the override is not automatic for me, and I run an exercise-nutrition research lab. So here’s what the data actually says about when and how to fuel.

Eat something before you train

In Wingfield et al. (2015), we measured resting energy expenditure, how many calories the body burns at rest, after women consumed protein vs. carbohydrate before a training session. Pre-exercise protein elevated that number in a way carbohydrates did not. The session ended; the metabolic benefit from fueling beforehand kept going. In plain terms: what you eat before training changes what your body does for hours afterward, not just during.

We followed that with Pihoker et al. (2019), a six-week study in trained women comparing a protein-carbohydrate supplement before training, after training, or not at all. Pre-exercise came out ahead for strength and body composition. Post-exercise also produced real gains. So if you miss the pre-workout window, eating after still counts — going in with nothing, consistently, is the only version that actually costs you.

With Hirsch et al. (2021), we looked at essential amino acids, the building blocks your body can’t make on its own, consumed 30 minutes before high-intensity exercise. Women showed particularly favorable responses when EAAs were added to training, with improvements in muscle size and quality over eight weeks. The practical version of this doesn’t require a supplement: real protein (eggs, Greek yogurt, a shake..) 30 to 60 minutes before you train does most of the same work.

Why eating earlier matters

Most women eat their biggest meal at dinner. Small breakfast, light lunch, everything at the end of the day. The problem is that by the time dinner arrives, training has already happened, the pre-workout window was missed, and the body is winding down rather than building.

Your muscles need a signal to grow. That signal gets triggered by protein, specifically about 3 grams of leucine per meal, an amino acid found in most animal proteins. Below that threshold, the building signal doesn’t fully fire. Above it, it does.

The foods that cross it: eggs, chicken, fish, Greek yogurt, whey protein. Two eggs and some yogurt at breakfast gets you there. A coffee and a handful of almonds does not.

Aim for 25 to 30 grams of protein at each meal, starting at breakfast. If your first real protein hit comes at dinner, your muscles have been waiting since morning.

What under-fueling actually costs

When dietary energy consistently falls short of what activity demands, the hormonal system that regulates the menstrual cycle starts protecting more essential functions. Cycles can become irregular, and injury risk rises alongside it.

Research on relative energy deficiency in sport, work I’ve been part of, shows that athletes with menstrual disruption report significantly higher rates of severe musculoskeletal injuries (both tracing back to the same upstream cause): not enough fuel (Cabre et al., 2022).

Menstrual irregularity in an active woman is often dismissed as a side effect of training hard. If your cycle has become irregular since ramping up training, or you’re getting injured more than seems reasonable, under-fueling is worth looking at before anything else.

None of this means every workout requires a full meal beforehand or discounts a ‘girl dinner.’ I run after just a cup of coffee more often than I’d like to admit, and there are weeks where I get to a short lifting session without having eaten anything first.

In both of those scenarios, I grab something with protein and carbs right after. A protein shake, greek yogurt, a full meal, whatever is fast absorbing. The issue isn’t the occasional fasted session. When under-fueling becomes the consistent pattern, that’s when the body starts making trade-offs.

On carbohydrates

This shouldn’t need its own section, but it does. Carbohydrates fuel the training that builds the muscle that supports everything else your body is asked to do. Paired with protein before a workout, they help you build rather than just survive the session. Rice, oats, fruit, toast before training are not indulgences. They’re what makes the protein you eat actually useful. The cultural message that carbs are something to earn or minimize around training is at direct odds with the physiology.

The minimum feasible version

I’ll be honest: I don’t always execute this perfectly. I’m in the lab early, my kids are up early, and some mornings the protein at breakfast is more aspirational than actual. But the data is consistent enough that I take it seriously when I can.

In order of what matters most:

• 25-30 grams of protein at breakfast

• Protein and carbohydrates 30-60min before training

• Something with protein right after training (especially if you trained fasted!)

• Fuel distributed across the day, not concentrated at dinner!

It’s just shifting when you eat what you’re already eating.

The messaging most of us grew up with was designed around aesthetics rather than what the physiology requires. Eating like a girl, if we mean anything useful by the phrase, looks like treating fuel as necessary rather than excessive.

Girl dinner is a real thing. I’m not above it. But the version that serves you has protein in it.

-Abbie

I say that as someone who has studied it for more than two decades and still finds it remarkable: give the body the right stimulus and it changes. It just requires that we understand what inputs it actually needs.

Body composition measurement is how you figure that out.

Not for comparing yourself to a chart, or hitting a number someone else decided was optimal, but for learning your own physiology: where you’re strong, where something warrants more attention, and what is actually changing with time and training.

I’ve been measuring my own body composition every nine months for 20 years. The data has surprised me repeatedly. When I was a collegiate distance runner, my coaches told me to get to 15% body fat. I worked toward it, got there via skinfolds, and then kept getting injured. The explanation I was given: low bone mineral density. It was wrong. My bone density has always been well above average, which I only knew because I eventually had the data to show it. The real problem was that I was being driven toward a number that made no sense for my body.

That experience is a big part of why I do this research.

What a DXA scan actually gives you

DXA stands for dual energy x-ray absorptiometry. It uses two low-dose x-ray beams to separate fat mass, lean soft tissue (the muscle, organs, and fluid that isn’t fat or bone), and bone mineral content. The scan takes 3 to 6 minutes and gives you a level of detail no scale or BMI calculation can match.

Most people who get a DXA scan immediately look at one number: total body fat percentage. I understand why, but it is the least useful thing on that report for tracking how your body is actually changing over time.

What I pay attention to instead: whole-body lean soft tissue, regional lean mass broken out by arms, legs, and trunk, visceral fat around the organs, and total body bone mineral content. These are the numbers that tell you whether training is working, whether nutrition is supporting recovery, and whether something is quietly changing that warrants attention.

Why lean mass is the real story

Lean mass is the engine that drives resting metabolism, supports joints, protects bone, and keeps you functional as you age. Losing lean mass without knowing it is one of the most consequential things that can happen to a woman’s body over time, and the scale will not tell you it’s happening. It also can be prevented.

I had a patient in our lab, a 47-year-old woman in a medical weight loss program. Over 13 months, she lost 45.6 lbs. On the scale, that looks like success. Her DXA data told a fuller story: of that total weight lost, approximately33 lbs was fat mass and approximately 10 lbs was lean muscle mass. Body fat percentage dropped from 42.7% to 34.8%, which is meaningful. But lean mass declined from 56.6 kg to 51.9 kg, and without DXA, we wouldn’t have known to address it. This was before GLP-1 medications existed, so plain caloric restriction. We can intervene on lean mass loss with protein targets, resistance training, and strategic fueling, but only if we’re measuring it.

The scale going down and body composition improving are related but not identical, and the gap between them is where the actual intervention lives.

Image: DXA scan from patient over 13 months, showing declines in fat mass and lean mass

The numbers only matter if conditions are controlled

Every device has error, and DXA is no exception. For total body fat percentage, you need roughly a 2.6% change to be confident you’re seeing something real rather than instrument noise. For lean mass, the threshold is approximately 2.75 kg. This is why monthly DXA scans are almost never informative. Scanning every 6 to 9 months gives the body time to change in ways the device can reliably detect.

Consistency of conditions matters as much as timing. Same machine every time, ideally same manufacturer: Hologic and GE-Lunar are calibrated differently, so comparing across them is like measuring with two different rulers. Come in fasted, or at least the same number of hours post-meal as your baseline. Muscle glycogen affects fluid distribution, so a carb-depleting workout the night before will shift your numbers, just as a carb load will. Injury, inflammation, even metal in your clothing affects results. That’s the part most people skip, and it’s the part that makes the data usable.

My own data across two decades

I’ll be the first to say the numbers aren’t always exciting. Pregnancy does things. Stress does things. Life seasons change your body. But my whole-body lean mass has stayed within a narrow range across more than 20 years of tracking, and my composition has actually shifted in ways I’m proud of. My most recent scan at 42 shows 106lbs of lean mass, and my fat distribution has improved with age: the android-to-gynoid ratio, which reflects where fat sits on your body relative to your hips, has remained stable, except for two measurements taken 3 months postpartum, which, sure.

My grad students keep getting younger. They tell me I have science on my side, and they’re right. I train smarter and fuel smarter than I did at 25. The data tells me what to adjust and when, and I actually use it.

Image: My body recomposition (loss of fat, increase in muscle) after resistance training; this gal (and all women) can build muscle while losing fat!

Whole-body DXA is not a bone density scan

A bone density scan ordered for clinical purposes targets the hip and spine specifically, and the T-score at those sites is what determines an osteoporosis diagnosis. A whole-body DXA scan is not designed for that and cannot substitute for it. Whole-body bone values tend to read higher than site-specific scans, so the numbers are not interchangeable.

What whole-body DXA does give you is a broader picture of skeletal health over time. In our research with midlife women, we’re seeing a meaningful number presenting with low whole-body bone mineral content, joint pain, and family histories of osteoporosis. For those women, the scan becomes a tool for advocacy: take this to your physician, ask about a dedicated bone density scan of the hip and spine, and push until you get a real answer.

So is it worth it?

A whole-body DXA scan typically runs $100 to $175 per session, and it often comes without any professional interpretation. You walk out with a printout full of numbers and no guidance on what to do with them. That’s a real limitation, and if cost or access is a barrier, it matters.

Bioelectrical impedance analysis (BIA) is worth knowing about. These are the devices on gym floors, in physicians’ offices, and in a growing number of home scales. They estimate body composition by sending a low-level electrical current through the body, since fat and muscle conduct electricity differently. The absolute numbers BIA produces often differ meaningfully from DXA values, and accuracy varies across devices. For tracking change over time, though, BIA can be genuinely useful when you use it consistently: same device, same time of day (morning, after going to the bathroom), fasted, and not within 24 hours of a hard training session. Under those conditions, the trend is real even when the single-point number isn’t perfectly precise.

I’ll be doing a full post on how different measurement methods compare and how to choose what makes sense for your situation. For now: if DXA is accessible and the cost is feasible, it gives the most complete picture. If it isn’t, a quality BIA device used consistently will still give you meaningful data to work from.

How I actually use this

I scan after different training phases because different phases create different changes. After a running-heavy season, lean mass tends to drift slightly. When I shift toward heavier lifting with higher protein, it comes back. That information tells me what to adjust going forward, not based on how I feel about the number, but based on what’s actually moving.

The number worth tracking is not your body fat percentage. It’s whether your lean tissue is going up, holding steady, or quietly declining over time. And if you’re in your 30s or 40s and your whole-body bone mineral content is coming back low, that’s worth taking seriously now, when intervention actually has traction. Be an advocate for yourself. Don’t take no for an answer.

-Abbie

The question I’ve been studying since before “HIIT” appeared in a fitness class name: how much exercise do you actually need for health, and does breaking it into short bursts count for anything?

It does.

The research community calls this approach exercise snacks, meaning short bouts of vigorous activity, 60 seconds or less repeated 3-4 times across the day without a gym, a training block, or an hour you don’t have.

The efficiency argument

What surprised me most about the early interval training research, including findings from MacInnis & Gibala, 2017 and Gibala et al., 2012, was how fast the adaptations happen. Not months. As few as 6 HIIT sessions over 2 weeks produced measurable increases in cardiorespiratory fitness, fat burning, and insulin sensitivity, meaning how efficiently your body clears blood sugar. The mitochondria, the cellular engines inside muscle, increase in density and function, making the body more metabolically efficient even at rest - which means exercise feels easier faster. And honestly, I want people to feel good exercising, it’s how we stick with it.

One of my first studies at UNC explored the effects of HIIT (10 x 1 min hard-1 min easy) compared to 5 x 2 min hard:1 min easy in 44 overweight men and women completed over 3 weeks (3 x per week) and showed significant increases in muscle cross-sectional area, a direct measure of muscle size and quality. Follow-up work with 66 overweight adults over 8 weeks replicated this in the HIIT group, alongside meaningful reductions in fat specifically around the abdomen. That location matters more than most people realize. Visceral fat, the fat stored around your organs rather than under your skin, is what drives insulin resistance, elevated cardiovascular risk, and metabolic dysfunction. HIIT targets it.

Funny little story, our ethics review committee thought this was too dangerous and was very skeptical. I obviously finally got approval, and even better, there were no injuries, and the enjoyment of this exercise was so high we have since used it in knee osteoarthritis patients, bone marrow transplant patients, and endometrial cancer patients - among others!

3 to 10 minutes of intense work can produce a physiological stimulus that 45 minutes of moderate cardio often doesn’t. This is not about a better approach - both types of exercise will get you there, one is just more time efficient.

What the data shows for exercise snacks

A 2025 meta-analysis by Chen and colleagues, published in Frontiers in Cardiovascular Medicine, synthesized 27 studies and 970 participants specifically on exercise snacks (remember- like little bite sized exercise bouts throughout the day). Nine out of eleven cardiometabolic measures improved significantly: cardiorespiratory fitness, body fat percentage, waist circumference, blood pressure, fasting blood glucose, and cholesterol markers.

Weight on the scale didn’t shift much, because short bursts can’t fully override a full-day energy equation. But the internal picture changed in ways that matter for how long you live and how well your body functions. Hands down, more important than how you look.

Stair climbing has some of the strongest data here. Boreham and colleagues documented a 17.1% increase in cardiorespiratory fitness after 8 weeks of short stair-climbing bouts in sedentary young women. A separate study by Michael, White & Eves found that climbing a 32.8-meter staircase at full effort, 5 days per week for 8 weeks, produced significant fitness improvements, not athletes by any definition, just people using a staircase a few times a week.

Blood flow is so good for the body and brain!

One key mechanism behind these benefits is something called blood-flow-induced shear stress: the force of blood moving rapidly through vessels signals the vascular walls to become more flexible and responsive (Islam, Gibala & Little, 2022). This is how short, intense bouts improve how your blood vessels function even without a traditional training program, and why the effects show up so quickly.

That mechanism doesn’t stop at the neck. The brain is one of the most metabolically demanding organs in the body and is highly sensitive to changes in blood flow. High-intensity exercise also triggers a surge in adrenaline and noradrenaline, and upregulates BDNF, a protein called brain-derived neurotrophic factor that supports the growth and connection of neurons.

Research on exercise snacks and HIIT with cognitive function points toward improvements in working memory, executive function, attention, and anxiety following high-intensity bouts. The mechanism is the same either way. A quick set of stairs before a meeting is not only a cardiovascular intervention, but can also help blood flow to the brain. My mid-life brain says YES PLEASE!

What I actually do

I try to exercise most days of the week (more for my brain than anything). I also love high intensity work and exercise snacks on days that I don’t have dedicated exercise time. I do push-ups before I give talks. It started as nervous energy in a conference hallway and became something I now plan for. My brain works noticeably better in the first few minutes after I’ve moved, and my nerdy self has decided this counts as non-negotiable pre-presentation prep.

On days when I have 10 minutes and nothing else, that’s enough. Ten sets of one minute hard, one minute easy, on a treadmill or a bike or just stairs. Anyone can do anything for a minute.

On travel days, I stop at rest stops and do jumping jacks or lunges. In airports, I walk fast between gates, and on longer layovers I find a wide hallway and move for about 90 seconds. I get some looks. At this point I’ve stopped noticing. Also an excuse to wear clothes to move in

The minimum feasible version

Exercise snacks don’t require equipment. They require intensity. Light walking doesn’t generate the same vascular or metabolic signal, so the burst actually needs to feel hard to count. Just to be clear - this doesn’t mean don’t enjoy a walk!

Some specific options that actually work:

• Run the stairs in your building rather than walking them

• Ten push-ups between tasks or right before a call

• 45 seconds of jumping jacks on the hour, or team push-ups on the hour if you have colleagues willing to commit

• Walk a meeting instead of sitting through it

• Bodyweight squats in a stairwell before a presentation (no one is watching, I promise)

• Sprint to the next corner when you’re already outside
  

The accumulated effect across a day is real, even when it doesn’t add up to a full training session, and that’s not actually the comparison worth making. Health outcomes separate not on the good weeks but on the hard ones, and on those days, 60 seconds moves the physiology. Exercise has stronger evidence for preventing chronic disease than almost any pharmaceutical intervention available. The feasible dose is considerably smaller than most people think. Some research shows as little as 11 minutes per day can reduce mortality- we all have time for that!

Start where you are, even when that starts with one flight of stairs. Next time you see me, let’s snack together.

Most of the women I talk to genuinely cannot tell if they’re eating too little, too much, or just the wrong kind.

I get it. For most of our lives the message to women was eat less, move more, shrink. Then the dial swung the other way. The whiplash is real (and lack of feasibility in hitting such high protein targets) makes it worse.

So let me try to do that differently.

The number worth building toward is 1.6 grams of protein per kilogram of body weight, every day. For a 150lbs woman, that’s ~109 grams. Not an aggressive target, just the floor where she’ll start seeing muscle-building results. For most women it’s considerably higher than what they’re currently eating.

Why distribution matters as much as total

Total daily protein matters, but how you space it matters just as much.

The muscle-building signal requires 25 to 30 grams of high-quality protein in a single meal. Smaller amounts spread thin across the day don’t trigger the same response. The reason is something called anabolic resistance: as we age, muscle tissue becomes progressively less sensitive to amino acids, the building blocks protein breaks down into. The dose that produced a clear muscle-building signal at 25 grams in your early 30s requires closer to 30 to 40 grams to produce the same result in your mid-40s.

This is one of the more underappreciated mechanisms driving body composition changes in midlife, and it’s almost never part of the conversation women are having with their providers.

30 grams looks like four eggs and a slice of cheese, or a cup of Greek yogurt stirred with 2 tablespoons of hemp hearts. Three meals at that dose gets most women to around 90 grams. A protein-forward snack or a shake then closes the gap.

Why whole foods do more work

Whole food protein does more than hit a gram count. Your body burns more calories processing it than it does digesting a liquid, and the fiber and micronutrient profile a whole food delivers simply can’t be replicated in a shake. The same gram count from chicken and lentils vs. a processed bar produce meaningfully different body composition outcomes over time.

Leucine content is part of why. Leucine is the amino acid that most directly triggers the muscle-building signal, and its concentration varies considerably across protein sources. Animal proteins tend to have higher leucine density than most plant sources at equivalent gram counts. Though, to be fair, plant proteins aren’t ineffective, the target just likely needs to run higher if the diet is primarily plant-based, probably closer to 1.8 to 2.0 grams per kilogram, to compensate for lower leucine availability.

Shakes and bars have a real role around training, on travel days, when dinner is not happening at 6:15pm, but the default should still be whole foods.

The protein maxxing problem

I was quoted in Oprah Daily earlier this year on exactly this. The short version: piling protein in through ultra-processed protein products can backfire in unexpected ways, including weight gain. A lot of those products spike insulin in a way whole food doesn’t, and if there’s no training pulling the amino acids and glucose toward muscle tissue, the body composition outcome isn’t what the marketing implies.

Training consistently, 2 to 3 resistance sessions per week, is what makes higher protein intake work. Without it, you’re largely adding calories in a package that feels effective because it has a macronutrient label on the front.

Water and fiber have to keep pace

When your body metabolizes protein it cleaves off nitrogen and clears it through the kidneys. More protein means more nitrogen to flush, and that draws on hydration.

An extra glass or two of water on days you’re hitting the target is a reasonable practical adjustment, and one most people skip.

Fiber is the other piece. Women in their 30s, 40s, and 50s consistently under-eat it, and the deficit gets worse the more protein-forward the day becomes. Animal protein on its own can reduce some of the gut microbiome diversity that fiber supports.

Pairing protein with something fibrous at each meal, eggs with berries, chicken with lentils, addresses both at once.

What I actually do

I don’t always hit 1.6 grams per kilogram. Some days breakfast is a coffee and a protein pancake on the way out the door, which has maybe five or six grams of protein in it. A target gives your decisions a direction even on the days you fall short.

Your body will usually signal under-fueling before you consciously register it: soreness that lingers past 48 hours, workouts that feel harder than they should, sleep that isn’t producing the recovery it used to. None of those alone tells you much. Stack two or three and they’re worth bringing to a provider, not just struggling on your own.

Where to start

Pick the meal you skip most often and get it to 30 grams of high-quality protein paired with something fibrous.

If you’re already doing that, push the second meal, then the third. It’s all relative to where you’re starting.

- Abbie

By the time most women find their way to my lab, they’ve spent years eating less and exercising more. Their scale hasn’t moved in months. Their energy is gone. They’re hungry, exhausted, and watching the scale creep up despite doing exactly what they were told.

It isn’t willpower. The metabolism has been told, for years, that food is scarce, and it has adapted accordingly.

I lived in that exact place after college. Ten years of distance running put me in a chronic energy deficit, and when I stepped away from competition my body did what bodies do under those conditions. It held onto every calorie. My resting metabolism dropped well below what predictive equations said it should be.

That’s actually what pushed me toward a physique competition years later. My nerdy brain wanted to see what the body would actually do under structured contest prep. The answer was interesting and humbling. I dropped a meaningful amount of fat and came out the other side completely metabolically adapted.

Rebuilding from there took more food, more protein, and resistance training.

The body is not a calculator

60% to 70% of your daily calorie burn happens at rest, before you’ve lifted a weight or taken a step. Exercise, daily movement, and digestion make up the rest. When you cut calories, all four shrink.

Resting metabolism falls more than the math would predict. The hormonal environment quietly shifts: hunger hormones rise, satiety signals drop, and the whole system tilts toward storing fat and breaking down muscle, as our lab documented in 2014.

The harder part is that those changes outlast the diet. A 2008 study found that subjects who had maintained weight loss for over a year still showed suppressed resting metabolism. For me it persisted for a few years.

Your body has a budget

The body has a fixed energy budget, and it’s better at protecting it than most fitness advice assumes. Research by Pontzer and Trexler found that when you increase physical activity, the body compensates by reducing energy spent elsewhere. A fun fact: Hadza hunter-gatherers, who walk 8 to 10 miles a day, burn roughly the same total daily calories as sedentary office workers of the same body size.

This is why hours of added cardio rarely produce the fat loss the math implies. Your body finds places to save energy, often by trimming hormonal output and slowing recovery. The composition of how you spend the budget matters more than the size of the budget itself.

The muscle myth

You’ve potentially seen the claim that muscle burns 50 calories per pound. The real number is about 6 calories, and fat burns about 2. So yes, muscle burns more than fat, just not by the margin that gets repeated in fitness circles.

Fat tissue burns calories at rest too, just not as much as muscle. In one of our studies, women with higher body fat were burning about 281 more calories per day at rest than the leanest group, simply because they had more metabolically active tissue overall. Most of them had been eating well below what their body was actually burning at rest. For many, eating less had been making the problem worse.

Where muscle earns its reputation is in the rebuild. Training, repairing, and maintaining muscle costs calories every day, layered on top of resting expenditure. The advantage of muscle is that it makes your metabolism resilient when life isn’t perfect, which is most of the time.

Your menstrual cycle can shift the math

Estrogen shifts how your body uses fuel. In the luteal phase (the second half of the cycle), resting metabolism rises by roughly 100-300 calories per day, per research going back to the late 1980s. That increase is part of why so many women crave sugar and sweets in the days before their period. The body is asking for more fuel, and the cravings make sense in that context.

If your training feels harder the week before your period, that isn’t in your head. Eating a bit more that week isn’t a failure of willpower, it’s the body running a different energy equation.

Perimenopause changes the rules

If you’ve noticed your body responding differently to the same strategies that worked at 35, this is part of why. In perimenopause, fluctuating estrogen affects fat distribution, muscle protein synthesis, and recovery. The body becomes less responsive to the muscle-building signal from protein. Women in their forties often need 30 to 40 grams per meal to get the same response that a lower dose triggered in their twenties. Sleep disruption from hot flashes and night waking compounds the problem by limiting recovery and shifting cortisol patterns.

The standard calorie calculators make this worse. In data we just published in the Journal of the American Nutrition Association, those equations overestimated resting metabolism in perimenopausal women by about 215 calories per day — 1,505 calories of unexplained difference over a week. They weren’t built for this life stage, which means women following them are often eating less than their body is actually burning at rest.

In some of our studies, we’ve measured resting metabolism as low as 600 to 800 calories per day in midlife women with reasonable lean mass. The common driver was years of chronic dieting and prolonged fasting, both of which suppress metabolic rate over time.

What actually works

Prioritize intervals over steady cardio. In our 2015 trial, 10 rounds of 60-second running efforts at 85 to 95% of maximum produced about 189 more calories per day of post-exercise resting metabolism than 30 minutes at a moderate pace. Roughly 20 minutes of actual work outperformed 30 minutes of steady cardio.

Eat some protein before those sessions. Women in the same trial who had 25 grams of whey protein (90 calories) before exercise burned more fat at 30 and 60 minutes post-session and had resting metabolism about 59 calories per day higher than those who had the same calories from carbohydrate.

Keep total protein high throughout the day, not just around training. Most women I work with are under-eating it. The target I use is ~1.0 grams per pound of body weight, at a minimum of 30 grams per meal. For a 150-pound woman that’s roughly 4 meals and a snack at ~140-150 grams a day. The evidence on this is consistent, higher protein preserves lean mass when calories are lower. This shouldn’t be your life’s mission, and if you hit 120 grams (0.8 g per lb) - that’s great! It’s about reframing your thinking to build your meals around protein first, but not only protein.

Fiber from real food. Most American women are coming in around 15 grams per day, well below the 25 to 35 grams that support satiety and blood sugar stability. Get there with beans, oats, and dark leafy greens.

Sleep. In a 14-day calorie deficit study, participants who slept 5.5 hours per night lost 55% less fat than those who slept 8.5 hours, despite eating the same amount. Short sleep drops leptin, raises ghrelin, and elevates cortisol, all of which push toward hunger and fat storage.

Lift weights, consistently. Two to four sessions a week is enough, particularly for protecting lean mass when calories are lower. In a 12-week trial, participants on an 800-calorie diet who added resistance training preserved lean mass and resting metabolism, while those doing aerobic training alone lost both.

One more thing

Year after year in the lab, I’ve watched women rebuild metabolisms they thought were permanently stuck. It takes longer than anyone wants, and it usually requires eating more than they’ve been told to. But the body responds. I’ve seen it enough times in the lab, and in my own body, to trust it.

-Abbie

“I’m eating protein at every meal, lifting, jumping, trying to sleep eight hours and I’m still tired.”

I’ve heard some version of that sentence more times than I can count. The details shift: a thirty-eight-year-old who’s wiped out by 2pm and can’t figure out why, a woman in perimenopause whose labs came back normal but who knows something is off, a former athlete who eats well and moves consistently and still feels like her body became a stranger somewhere around forty-five. They almost always end the same way: nobody gave them a real answer.

That’s not a personal failing. It’s a translation problem. Research on how women’s bodies actually change with age and hormones has grown enormously in the last decade, and most of it is still sitting in journals. The gap between what the science shows and what women actually hear is the reason I’m writing this: one paper, one mechanism, one thing you can do with it in your real life.

Who am I

I’m Abbie. I’m a PhD exercise physiologist and nutrition scientist at UNC Chapel Hill, and I’ve spent 25 years studying how women’s bodies change, adapt, and respond across the lifespan. I have 230-something peer-reviewed publications, which sounds more impressive before you account for how many of them involved very early mornings in an office with no windows.

Before any of that, I was a collegiate distance runner. Cross country, the 1500, the 5K. I ran myself into the ground. A little physiology and nutrient timing would have gone a long way.

I’m also a mom of two boys, which means I’m rarely the first person in my house to eat breakfast. I don’t always have time to fuel before I train. Some days are better than others.

I’ve measured my own body composition every nine months for 25 years, not because I’m obsessive about the number, but because the human body is incredibly adaptive and I believe in tracking what you can’t always feel in real time. I take creatine, omega-3s, magnesium, and vitamin D. I was a supplement skeptic for a long time: the research changed my mind, and that’s a different thing from just selling you something.

And I’ll be honest: every experience I’ve personally had with a healthcare provider in this space has been invalidating. Every single one. That frustration doesn’t drive the research, but it absolutely drives the writing.

Every time I design a study, I’m thinking about the woman on the other side of it. Her schedule. Her goals. Her perimenopause. Her postpartum body. Her kids. Her stress. Her wins. The science is for her, by her.

What You’ll Find Here

Each post here takes one study, translates the mechanism into plain English, and gets to the part that actually matters: what you do with it. It’s about more tools in the toolbox. Not every woman needs the same tools. Not every tool works for every woman. I’ll tell you when the evidence is strong, when it’s still emerging, and when I’ve changed my own view. If I’m saying the exact same things in 10 years, it means I stopped paying attention somewhere around year five.

The science communicator and the researcher are the same person here. I think that distinction matters more than it used to. The science gives us options, my job is to help you pick the ones that fit your life right now. Because here’s the truth: every day is a new day to choose yourself. That’s the real key to health and longevity. Not a perfect protocol. Not a 30-day reset. Just you, choosing you, today, with better information than you had yesterday.

What’s Coming

• Inside the lab: what my team and I are studying, why we designed it that way, and what it means for women long before it reaches headlines

• Inside the research: how to read a study, interpret the findings, and spot when conclusions go beyond the data

• Inside protein: how much women need, when it matters most, and why standard recommendations often fall short

• Inside strength training: how to build muscle, support bone health, and train for longevity

• Inside conditioning: HIIT, steady state, recovery, and what the evidence actually says

• Inside women’s physiology: training and fueling through menstrual cycles, pregnancy, postpartum, perimenopause, and menopause

• Inside recovery: sleep, alcohol, caffeine, creatine, supplements, and the habits that actually move the needle

If you’ve ever been told your labs look normal when something felt off, if you’re just tired of advice that never quite accounts for how women actually live, if you want the science without the noise -

You’re in the right place. More soon

- Abbie