Posted by Mark Nessim
Reviewed by Dr. Mark, Physician & Formulator
Here is a thing most people assume about losing weight: once it comes off, you move more. Stairs get easier, knees complain less, and the activity takes care of itself.
A study presented at the Endocrine Society's annual meeting in June 2026 checked whether that actually happens on a GLP-1 medication. The answer, in that dataset, was no.
What the study found
The researchers used the NIH's All of Us Research Program, which links participants' electronic health records to their own Fitbit data. Of 1,950 adults with obesity who started a GLP-1 receptor agonist (the class that includes semaglutide, sold as Ozempic and Wegovy, and tirzepatide, sold as Mounjaro and Zepbound), 753 had enough wearable data to analyse. The cohort was mostly women (78.6%), with a mean age of 52.7.
Comparing each person before and after starting the medication: daily steps fell from 5,047 to 4,487, and moderate-to-vigorous activity fell from 28 minutes a day to 22. The largest declines were in men and in people with joint or muscle pain. The authors found no evidence that the weight loss produced more physical activity. In the lead author's words, the findings reinforce that exercise "cannot be optional" for people taking these medications. (Maharjan S. et al., presented at ENDO 2026, Chicago, 13 June 2026; Endocrine Society press release.)
Read the small print first
This is a conference presentation, not yet a peer-reviewed paper, and it should be weighted accordingly. It is a retrospective before-and-after comparison with no control group. It could only include the 753 people, out of 1,950, who wore their tracker enough to be analysed, which selects for the kind of person who wears a tracker in the first place. And a drop of 560 steps a day is a real change but a modest one.
It is, however, the first large wearable-data look at the question, and it points the same direction as the smaller reports before it. We would cite something stronger if something stronger existed.
Why it matters more on a GLP-1 than off one
When weight comes off quickly, some of what goes is lean tissue. How much depends on three things: how fast the weight is coming off, how much protein is coming in, and whether the muscle is being asked to do anything. The medication sets the pace. The other two are yours.
Protein
A 2026 review in Metabolites puts the consensus target during active weight loss at 1.2 to 1.5 grams of protein per kilogram of body weight per day. In a cross-sectional study of people currently taking a GLP-1 that the review cites, only 43% were reaching 1.2 g/kg. The same review is candid that no randomised trial of protein supplementation during GLP-1 therapy has yet reported; one is registered and expected to read out in 2027. (Metabolites 2026;16(6):364.) We wrote a fuller guide to working out your own number in How Much Protein Do You Actually Need on a GLP-1?
Load
The 2025 joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association and The Obesity Society states that protein intake on its own is not adequate to preserve muscle without structured resistance training. The Fitbit study is the reason that sentence is not a formality: the default, absent a deliberate decision, appears to be less movement rather than more. No powder substitutes for lifting something heavy twice a week. Our earlier post on preventing muscle loss on Ozempic and Wegovy goes into the training side in more detail.
If part of the reason you are moving less is that you are simply tired, that is common and has its own causes; see Why GLP-1s Make You Tired.
Where creatine fits, and where the evidence is thin
Creatine monohydrate is in ASP-1, so it is fair to ask what it does. The better-established story is muscle and bone alongside resistance training, which brings us back to the point above. The cognition story is newer and weaker. A systematic review published this year in Nutrition Reviews looked at creatine and cognition in adults over 55: six studies and 1,542 people in total. Only two were double-blind supplementation trials; the other four estimated creatine from dietary recall. Five of the six reported a positive association, mostly for memory and attention, but the authors rated one study good, two fair and three poor, and concluded that the evidence is limited and that high-quality trials are still needed. (Nutrition Reviews 2026;84(2):333.) That is the honest summary: promising, not proven.
Where we come in, briefly
We make protein powder. We are not going to pretend the powder walks.
The honest split is this: the moving is yours, and the protein is the input that can be made easy. One scoop of ASP-1 Adaptive Support Protein, once a day, is 25 grams of total protein (20 g whey isolate plus 5 g collagen peptides) and 3 grams of creatine monohydrate, on the days when appetite is not cooperating and a plan is not happening.
For qualifying customers, ASP-1 may be eligible for HSA or FSA reimbursement with a Letter of Medical Necessity. Our checkout partner Flex runs a short telehealth questionnaire and issues the letter where appropriate; eligibility is determined on an individual basis. The HSA/FSA page presents the 90-Day Supply first, which is three months in a single order. If you have an FSA, many plan balances run on a calendar year; your plan administrator can tell you how yours works. We wrote about how the letter actually works in Are Protein Powders HSA or FSA Eligible?
"Bought it for myself first, my husband tried mine and ended up ordering his own tub. We do morning shakes together now, kind of a nice little ritual honestly."
Trent H. · Verified buyer
The short version
Assume the appetite is handled and the moving is not. Walk the 560 steps back. Eat the protein. Lift something twice a week. Treat the powder as the boring part that stays done.
This article is for general information and is not medical advice. Decisions about medication, exercise and supplementation should be made with your own clinician, who knows your history. Nothing here is tax advice; your plan administrator can tell you what your account allows.
These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
