Semaglutide and tirzepatide (Ozempic, Wegovy, Mounjaro, Zepbound) are the loudest medications of the decade. Advertising shows how fat disappears. It doesn't show what disappears along with it.<\/p>\n\n\n\n
A fresh RCT protocol from the Dasman Diabetes Institute (Kuwait) \u2014 LEAN-PREP \u2014 tries to answer the question everyone is avoiding: how to preserve muscle mass during pharmacological weight loss.<\/p>\n\n\n\n
In the STEP 1 trial\u2014a registration study of semaglutide 2.4 mg\u2014participants lost an average of 15% of body weight over 68 weeks. A separate sub-study involving DXA scans of 140 patients showed an overall reduction in lean mass of 9.7% from baseline.<\/p>\n\n\n\n
This is worth breaking down. If a person weighing 100 kg loses 15 kg, approximately:<\/p>\n\n\n\n
In other words, losing 25\u201335% isn\u2019t a big deal. In the context of standard diets, this isn\u2019t a disaster: with any energy deficit, some of the loss comes from muscle. But there are three factors that make GLP-1 a different story.<\/p>\n\n\n\n
First, speed.<\/strong> Losing 15% in 68 weeks is faster than people usually lose weight on an unsupervised diet.<\/p>\n\n\n\n Secondly, appetite.<\/strong> Semaglutide sharply reduces the feeling of hunger. This means a person may simply not eat enough protein. If the diet was 100g of protein a day, on semaglutide it's easy to eat 50g.<\/p>\n\n\n\n Thirdly, demography.<\/strong> The preparation is actively prescribed to people over 40 who are at risk of sarcopenia. Losing muscle in your 30s is bad; losing it at 55 is an accelerated trajectory to frailty.<\/p>\n\n\n\n A separate SEMALEAN study (2024, 115 patients, 12 months) painted a more optimistic picture: lean mass declined until the 7th month, then stabilised, whilst the proportion of sarcopenic obesity fell from 49% to 33%. But this is an average \u2014 individual variation is huge.<\/p>\n\n\n\n A single-centre, 6-month study of 232 obese adults. All participants were on semaglutide or tirzepatide. Randomisation was 1:1:1:1 into four groups:<\/p>\n\n\n\n The primary endpoint is the cross-sectional area of the quadriceps on MRI. Not weight, not DXA \u2013 specific tissue in a specific location.<\/p>\n\n\n\n The results are not yet available (this is a protocol), but the combination of resistance training + protein is what has been working for decades in other contexts: in older people with sarcopenia, in patients after bariatric surgery, and in those losing weight on a low-calorie diet.<\/p>\n\n\n\n The logic is simple. The drug reduces appetite \u2013 which means a person must consciously seek out protein, because passively there will not be enough of it. The drug does not stimulate anabolic pathways \u2013 which means the signal \u201cdon't break down muscle\u201d must come from outside, from mechanical load.<\/p>\n\n\n\n Muscles are not a cosmetic. Less muscle mass equals lower resting energy expenditure (RMR) which means easier weight regain after stopping the medication. And regain is not the exception. In the STEP-1 extension and SURMOUNT-4 (tirzepatide) studies, two-thirds of the lost weight was regained within a year of stopping treatment.<\/p>\n\n\n\n This means that a person who lost 20 kg on semaglutide without training and protein, a year after stopping it:<\/p>\n\n\n\n Not because the drug is bad. Because it was used insufficiently.<\/p>\n\n\n\n Strength training - 3 times a week. Large muscle groups: legs, back, chest, shoulders. 8-12 repetitions, 2-3 sets. At home with dumbbells or at the gym \u2013 it doesn\u2019t matter. Less energy on GLP-1, so short effective sessions are better than long enthusiastic ones.<\/p>\n\n\n\n Protein \u2013 1.6g per kg of body weight per day. For an 80kg person, this is 128g. Split into 3-4 meals. The hardest part is eating protein in the morning because appetite is zero on semaglutide. Hence, eggs, Greek yogurt, protein shake instead of \u201cI don\u2019t feel like it\u201d.<\/p>\n\n\n\n Creatine \u2013 3\u20135 g per day, monohydrate, no loading phase. The best-researched supplement for muscle preservation during a deficit.<\/p>\n\n\n\n Sleep \u2013 7+ hours. On sleep deprivation, catabolism wins.<\/p>\n\n\n\n The drug reduces not only appetite. It reduces thirst, fatigue, and the \u201cfeeling of food\u201d as a social ritual. In some people, it reduces mood. Strength training doesn't bring these things back \u2013 it only brings back muscles. If a person feels bad on semaglutide overall, adding weights won't be a salvation.<\/p>\n\n\n\n And furthermore, this is not an instruction to abandon medication for a \u201cnatural\u201d path. For a person with a BMI of 38 and type 2 diabetes, GLP-1 offers clinically significant benefits. It\u2019s simply that alongside it, you need what\u2019s not in the instructions: three resistance sessions per week and 1.6g of protein.<\/p>\n\n\n\n LEAN-PREP must conclude in the coming years and provide specific answers: does resistance + protein preserve quadriceps on MRI. If so, this will be the new standard for supplementation on GLP-1. For now, there are sufficient empirical reasons to start without waiting for this data.<\/p>\n\n\n\nWhat does LEAN-PREP offer?<\/h2>\n\n\n\n
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Why is this important specifically for GLP-1s<\/h2>\n\n\n\n
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What to do while waiting for LEAN-PREP results<\/h2>\n\n\n\n
What does this not solve<\/h2>\n\n\n\n
What to expect<\/h2>\n\n\n\n
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