Evidence explainerGLP-1 Companion
How Much Protein on a GLP-1? What the Joint Advisory and Expert Consensus Say
A 2025 joint advisory and a 2026 expert consensus both land near 1.2 to 1.6 g of protein per kg a day during weight loss, with a lower floor for maintenance. Which body weight to multiply by is still unsettled.
Key takeaways
- The general adult recommendation is 0.8 g of protein per kg of body weight a day, a value now under review by the National Academies [1].
- The 2025 joint advisory cites 1.2 to 1.6 g/kg a day as a proposed target during active weight loss, and says intake should not fall below 0.4 to 0.5 g/kg or stay above 2 g/kg for long periods [1].
- A 2026 international expert consensus recommends 1.2 to 1.5 g/kg of actual body weight a day during the weight-loss phase on a GLP-1, and at least 0.8 g/kg during maintenance [2].
- For people with obesity it is unclear whether to use actual, adjusted or lean body weight; the advisory notes a fixed 80 to 120 g a day may be easier to follow [1].
- Both documents say protein alone is not enough: strength training is what preserves muscle [1][2].
The targets side by side
These are population targets from guidance documents, not a personal prescription. Here is what each one says:
- General adults: 0.8 g/kg a day, the current recommended dietary allowance [1].
- During active weight loss: 1.2 to 1.6 g/kg a day has been proposed; 1.2 to 1.7 g/kg during strength training [1].
- During major weight reduction, expressed by adjusted body weight: 1.2 to 2.0 g/kg of adjusted body weight a day [1].
- On a GLP-1, weight-loss phase: 1.2 to 1.5 g/kg of actual body weight a day, or 25% to 30% of energy on a 1,600 kcal diet [2].
- On a GLP-1, maintenance phase: at least 0.8 g/kg of actual body weight a day [2].
- Adults over 65: at least 1.0 to 1.2 g/kg a day, at least 1.2 g/kg if active, and 1.2 to 1.5 g/kg with most acute or chronic illnesses [3].
Which body weight to multiply by
The joint advisory says that for people with obesity, multiplying by actual body weight can significantly overestimate protein needs; 1.5 g per kg of lean (fat-free) mass is considered more accurate but needs a body-composition measurement, and a fixed 80 to 120 g a day may help adherence [1].
The 2026 consensus chose actual body weight because most research uses it and it is simpler to apply in practice [2]. As arithmetic only: at 100 kg (220 lb), 1.2 g/kg of actual weight is 120 g a day, the top of the advisory’s fixed range.
Floors, ceilings and kidney disease
The advisory warns that intake below 0.4 to 0.5 g/kg a day can lead to muscle wasting and that prolonged intake above 2 g/kg a day should be avoided; protein beyond what muscle needs can be converted to fat [1].
People with severe kidney disease (eGFR below 30) who are not on dialysis may need to limit protein, an exception the PROT-AGE group spells out [3]. A 2026 clinical nutrition review proposes at least 1.2 g/kg a day, up to 1.6 g/kg in suitable adults without chronic kidney disease, with about 0.3 to 0.4 g/kg per meal [4].
How strong the evidence is
There is little direct trial evidence on protein needs during GLP-1 treatment. The 2026 consensus says its statements come mainly from indirect evidence, including bariatric nutrition guidelines and clinical experience [2].
The best indirect support is from diet trials: in a meta-analysis of 20 randomized trials in adults over 50 losing weight, higher-protein diets preserved more lean mass and lost more fat [5]. Protein still works alongside resistance training, not instead of it; see strength training on a GLP-1.
Getting it in with a small appetite
The advisory suggests eating protein-rich foods first in a meal and leaning on lower-volume options such as fish, eggs, Greek yogurt, cottage cheese and nuts or seeds; some people meet targets with protein shakes or bars [1]. When food intake is very low, the consensus says a high-protein oral nutritional supplement may be recommended [2].
Our whey protein and pea protein monographs compare powders, and how much protein to build muscle covers the training research.
Quick answers
Should I base my protein on current weight or goal weight?
Guidance differs. The 2026 consensus uses actual body weight [2]; the joint advisory says actual weight can overestimate needs in obesity and suggests lean-mass-based or fixed 80 to 120 g targets [1].
Is more than 2 g of protein per kg too much?
The joint advisory says prolonged intake above 2 g/kg a day should be avoided [1].
Do I need protein shakes on a GLP-1?
Not necessarily. The advisory lists shakes and bars as one way some people reach their target, alongside foods like fish, eggs and Greek yogurt [1].
More in GLP-1 Companion
- GLP-1 Companion hub
- Muscle Loss on Semaglutide vs Tirzepatide: What the Body Scans Show, and What Strength Training Adds
- Hair Shedding on a GLP-1: Why It Starts Months Later, Whether It Grows Back, and the Ferritin Question
- Stopping Wegovy or Zepbound: How Much Weight Comes Back, and What Happens to Blood Pressure and Blood Sugar
References
- [1]Nutritional priorities to support GLP-1 therapy for obesity: A joint advisory from the American College of Lifestyle Medicine, the American Society for Nutrition, the Obesity Medicine Association, and The Obesity Society. Obes Pillars, 2025.
- [2]Nutritional and lifestyle supportive care recommendations for management of obesity with GLP-1 - based therapies: An expert consensus statement using a modified Delphi approach. Obes Pillars, 2026.
- [3]Evidence-based recommendations for optimal dietary protein intake in older people: a position paper from the PROT-AGE Study Group. J Am Med Dir Assoc, 2013.
- [4]Medical nutrition in the glucagon-like peptide-1 (GLP-1) era: Protein strategies, micronutrient monitoring, and lean mass preservation. Clin Nutr ESPEN, 2026.
- [5]Effects of dietary protein intake on body composition changes after weight loss in older adults: a systematic review and meta-analysis. Nutr Rev, 2016.