Did the protein craze get you too?

Last week, I stood in the snack aisle at a corner market in San Francisco, counting…. Protein cookies. Protein popcorn. Protein water, and on and on and on. Protein Doritos? Not on my shelves yet, but I wouldn’t be surprised if it’s soon.

Suppliers who tell food companies what to make are betting on it.  But protein can feel overdone, like the terms “organic,” “natural,” and “keto.” It’s like when truffles are added to every menu item at a high-end restaurant.

The other difference today is that this science is better than ever. We know protein matters, and it matters even more as you age.

The devil is in the details.

Fat and carbohydrates are fuel. Protein is building material. You eat it, your gut breaks it into amino acids, and your body rebuilds those pieces into muscle, bone, enzymes, antibodies, and hormones that support health. Protein contains nine of twenty essential amino acids that your body can’t make on its own, giving it important real estate.

You can’t stockpile it, though. The body stores extra fat and carbohydrates but not protein. What you don’t use goes to the liver, which turns the nitrogen and your kidneys flush it.

One amino acid, leucine, helps tell muscles to start building. We can see this in a trial in older women, which pitted a big dose of whey protein against a much smaller dose of milk protein with extra leucine added. Surprisingly, the smaller dose worked about as well.

Leucine is still only a sign: muscles also need enough total protein and all essential amino acids to grow.

The official protein recommendation is 0.8 grams per kilogram of body weight a day — about 55 grams for a 150-pound woman. Most American adults already eat that, and more. Averages are tricky, though. About a third of older Americans miss even that minimum. The minimum might be too low for them anyway. 

Aging muscles need protein. To be exact, older adults might need roughly two-thirds more protein per meal than younger adults to start building muscles fully.  Most studies for adults age 65+ now land on an amount near 1.2 grams per kilogram — 40% above current guidance.

So a 30-year-old buying protein chips is solving a problem she doesn’t have. A 72-year-old who skips breakfast has a real problem. Food marketers talk to both age groups the same, anyway.

Again, protein matters as we age. I feel like that’s pretty clear. But the hype gets slippery fast, from GLP-1 weight loss to oversized protein servings, kidney fears, longevity claims, and labels that may not mean what they seem.

GLP-1s and Protein: What’s the connection?

Popular weight-loss drugs — Ozempic, Wegovy, Mounjaro — kill appetite, but that fast weight loss can cost you muscle and fat.  Doctors will tell those patients to covet protein,  and it’s opening an insane marketing opportunity. If protein protects muscle, anything with protein must be healthy, right? Even that cookie.

Breakfast: where protein goes missing

A protein rule many of us have heard a hundred times before is that your body can only use 25 or 30 grams in a sitting — that might be wrong. Maastricht University researchers gave men either 25 or 100 grams of tagged protein and tracked every gram for 12 hours. The 100-gram group kept building the whole time. 

When is it too much for your kidneys?

High protein has been said to wreck the kidneys in healthy people, but that also looks wrong. More protein seems to raise the kidneys’ filtration rate, but the rate stays normal — the organ is working, not failing. For people whose kidney function has already dropped, it’s a different story. Plenty of people past 60 have mild kidney trouble and don’t know it. That argues for a blood test, not panic.

For healthy adults, up to about 2 grams of protein per kilogram a day looks safe for the kidneys long term. Above that, researchers report digestive, heart, and kidney problems. Making urea also costs water — constant thirst and dark urine suggest you’ve overshot it.

Protein and your lifespan

In lab animals, less protein actually extends life by quieting two growth pathways — a hormone called IGF-1 and a cellular switch called mTOR. Less growth, longer life. But less muscle growth also means less muscle.

It’s observational, a pattern rather than proof, but it suggests that the protein script flips somewhere in your sixties. 

Influencers telling 45-year-olds to eat like bodybuilders and ones telling 75-year-olds to fast are each giving the right advice to the wrong people.

A “Good source of protein” meets 10% of your daily protein value. “High protein” meets 20%. Important to note is that the honest number considers how well you digest it. Beans with 6 grams and a middling score count as 3.6, meaning that label might not be telling the full truth.

The loophole: companies are allowed to print the raw gram count on the front without that adjustment, as long as the corrected figure sits in the Nutrition Facts panel on the back. The crude method that estimates protein by measuring nitrogen is allowed too. So the number on the front may be nitrogen.

Taking action still depends on having a doctor who can read the fine print and on the follow-through work you do yourself. Face it, we are on our own as advocates for our health.

Protein isn’t a scam, but the claims on the front of the bag may not be right. The food industry counts on you missing the difference. Here’s how I make sure I’m getting enough protein (and enough of the good kind).