WOMEN'S WELLNESS INSIDER

CLINICAL NUTRITION FOR WOMEN 40+

September 13, 2026 at 8:42 am BST

GLP-1 NUTRITION · EXPERT ANALYSIS

A Dietitian Explains the "Protein Gap" Almost Every Woman Hits on a GLP-1 — and Why "Just Eat More" Is the Worst Advice You Can Follow

"By the time a woman tells me she feels weak, tired and 'smaller but softer,' the intake problem has usually been running for months. She isn't failing at nutrition. The advice she was given simply doesn't work for a body whose appetite has been switched off."

— Dr. Claire Whitmore, RDN

Let me start where most of these conversations start: with a woman who did everything right, and still ended up frightened by her own reflection.

She's lost a significant amount of weight on a GLP-1 medication. For the first time in years, it worked. But somewhere around the four-to-six month mark, something shifted that the scale never showed her. She's tired in a way sleep doesn't fix. She's weaker — she notices it lifting shopping, climbing stairs, carrying a case. She looks in the mirror and she's smaller, but she's softer. And when she raised it with her doctor, she was told the same sentence I hear over and over: "just make sure you're getting your protein in."

Here is the problem with that sentence. It is, on its face, correct. And it is almost useless.

I'm Dr. Claire Whitmore, a Registered Dietitian Nutritionist. Most of my work now is with women navigating weight loss on medications like these. And the single most common thing I see isn't a lack of knowledge. These women know protein matters. They've read it a hundred times. The problem is that the one instruction everyone gives them is the one instruction their body has been medically engineered to refuse.

The mechanism nobody explains: the Protein Gap

Here's what's actually happening, and once you see it you can't un-see it.

A GLP-1 medication works — the whole reason it works — by suppressing appetite. It slows how quickly your stomach empties and it turns down the hunger signal. That's the mechanism of the weight loss. It's doing exactly what it's supposed to.

But that same mechanism creates a second effect nobody prepares you for. Your need for protein doesn't fall. If anything, during rapid weight loss it becomes more important, because adequate protein and strength work are what the clinical guidance points to for protecting your strength and shape while the weight comes off. Your need goes up. Your ability to physically eat goes down.

That space between the two — between the protein your body needs and the food you can actually get down — is what I've started calling the Protein Gap.

The protein gap

Your protein requirement stays high. Your appetite is switched off. The gap between them is where the trouble lives.

Every symptom women describe to me — the fatigue, the weakness, the "smaller but softer," the sense of getting frailer instead of fitter — traces back to weeks or months spent living inside that gap. Not because they're lazy. Because the food simply won't go down.

And "just eat more protein" doesn't close the gap. It's like telling someone who can't sleep to "just get more rest." You already know. That was never the problem.

WHAT NOBODY MENTIONED AT THE PHARMACY

Why the standard advice fails — every option, one by one

I've watched women try, in good faith, every conventional way to close the Protein Gap. Here's why each one tends to fail for a suppressed appetite:

"Just eat more protein." The appetite is medically suppressed. Five bites into a chicken dinner she's not full — she's at the "one more bite and I'll feel unwell" point. The intention is there; the capacity isn't.

A thick protein shake. A creamy, milky, 30-gram shake isn't a solution to not being able to eat — it is eating. It sits heavy. For a lot of women on these medications, the smell of it first thing is enough to turn the stomach. So the tub ends up in the cupboard, barely touched.

Protein bars. Dense and filling — often the last thing a suppressed appetite can face mid-morning.

"Prioritise it at meals." Same wall. If the whole meal is five bites, prioritising within it only goes so far.

The women who do best aren't the ones who force down the most protein. They're the ones who found a format they can actually finish on a bad day.

That last line is the entire point, and it's where the thinking has to flip. The goal was never the biggest protein number. Thirty grams left in the cupboard is zero grams. The only protein that helps you is the protein that makes it into your body. Completion beats quantity — every time.

What actually closes the gap

Once you accept that completion is the whole game, the solution gets simple. You stop asking "what has the most protein?" and start asking "what will she actually finish on her worst appetite day?" Those are completely different questions, and they lead to a completely different product.

01

It has to be light, not a meal

Clear and cold — closer to a juice than a milkshake. Nothing thick, creamy or heavy that competes with an already-full stomach.

02

The serving has to be finishable

A modest, sippable volume you can get down in a few minutes — not a giant shake to get through. A smaller amount finished beats a larger amount abandoned.

03

It has to fit the morning you already have

Thirty seconds, cold water, done. If it takes effort, a low-energy, low-appetite person won't keep it up — and consistency is the whole point.

This is exactly the brief I'd write for a product for these women. And it's why, when I was asked to review Mainstay, it was the first one I'd seen actually built around the completion problem instead of the protein-maximising one.

It's a clear protein — you mix it into cold water and it comes out like a cordial, not a shake. A modest serving of complete protein, with fibre, collagen and electrolytes alongside it. Light enough to sip on a low-appetite morning. As a dietitian, what matters to me is simple: it's a format a woman with a suppressed appetite is far more likely to actually finish. And the protein she finishes is the only protein that counts.

Why starting early matters more than women realise

This is the part I wish every woman heard on day one of her prescription, not month six.

Supporting your strength and intake from the start of the weight loss is meaningfully easier than trying to rebuild after months in the Protein Gap. The clinical guidance is consistent on this: adequate protein and resistance-type activity during weight loss help protect strength and lean tissue — and rebuilding, once you've lost ground, is slower and harder work than protecting it in the first place.

The earlier you start supporting intake, the easier it is

Start in the first weeks Easiest

Start once tiredness sets in Harder

Start after months in the gap Hardest

Directional illustration of a well-established nutrition principle — protecting strength and intake early is easier than rebuilding later. Not a prediction of individual results.

None of this means panic. It means that if you're early, this is the easiest it will ever be to get ahead of. And if you're already months in and feeling it — this is simply the moment to start, because every week you close the gap is a week working for you instead of against you.

REVIEWED BY DR. CLAIRE WHITMORE, RDN

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The finish-it guarantee

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DON'T SPEND ANOTHER MONTH IN THE GAP

The protein you finish is the only protein that counts

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Why women stay with it

Built for the days when eating is the hardest part.

A serving you'll finish beats one that impresses you.

10g in a light glass you actually drink, on the day you can manage five bites. Consistency does more than a big number you leave behind.

Clear, not creamy.

It mixes like a juice — no thick, milky texture sitting in your stomach. Something you can sip slowly instead of forcing down.

It slots into the morning you already have.

Protein, fibre, electrolytes and a light lift of caffeine in one cold glass — at the exact point in the day you were already reaching for something.

Protein for the intake. Creatine for the strength.

The 3-month protocol includes a full daily serving of creatine alongside the protein. Two simple habits that work together.

The easiest time to start is before it feels urgent.

Strength builds back slowly. Starting now means you're not waiting for the tiredness or the jeans to be the reason you finally act.

Lose the weight. Keep the strength.

Reserve my 3-month protocol

Mainstay research links:

The Race Is On to Stop Muscle Loss.

The acute effects of four protein meals on insulin, glucose, appetite and energy intake in lean men Managing the gastrointestinal side effects of GLP-1 receptor agonists in obesity: recommendations for clinical practice.

Preserving Healthy Muscle during Weight Loss1,2,3

Weight loss drug may change how obese people perceive taste.