How much protein you need, and when more helps

For most of the past two decades, US guidance treated 0.8 g of protein per kilogram of body weight a day as enough for nearly every adult. That number, the Recommended Dietary Allowance, is the amount that prevents deficiency in 97 to 98 percent of healthy people. It was never meant as the amount that is best for muscle, recovery or weight loss. In January 2026 the 2025 to 2030 Dietary Guidelines for Americans raised the target to 1.2 to 1.6 g/kg a day, adjusted to calorie needs.

The numbers, by source

For a 70 kg adult, 0.8 g/kg is 56 g a day; 1.2 g/kg is 84 g; 1.6 g/kg is 112 g. For a 100 kg adult on a GLP-1, 1.6 g/kg of actual weight would be 160 g, which is one reason the joint advisory offers the 80 to 120 g absolute range instead.

Older adults

Muscle responds less to protein with age. The PROT-AGE group, convened by the European Union Geriatric Medicine Society, concluded in 2013 that adults over 65 need at least 1.0 to 1.2 g/kg a day, 1.2 or more if they exercise, and 1.2 to 1.5 g/kg with most acute or chronic illness. The exception is severe kidney disease not on dialysis (eGFR under 30), where protein may need to be limited. The new US guidelines also note that older adults may need fewer calories but equal or greater amounts of protein, B12, vitamin D and calcium.

During weight loss

When you eat less, some of the weight lost is lean tissue. Protein and resistance training are the two tools that reduce it. The 2025 GLP-1 advisory cites modelling suggesting muscle may be 10 to 15 percent of weight lost in women and 20 to 25 percent in men without structured strength training. It also warns against going below 0.4 to 0.5 g/kg a day, which risks muscle wasting, and against staying at 2 g/kg or more for long periods. The muscle guide covers the training half, and GLP-1 muscle loss covers the trial data.

If you train

The International Society of Sports Nutrition puts the range for most exercising people at 1.4 to 2.0 g/kg a day, and notes that intakes up to 2.3 to 3.1 g/kg may help trained lifters keep lean mass during a calorie deficit. A widely cited meta-analysis, Morton and colleagues in 2018 (49 trials, 1,863 people), found that protein supplements added a modest amount to training gains, 0.30 kg more fat-free mass and 2.49 kg more on a one-rep max, and that above about 1.6 g/kg a day extra protein made no further difference to muscle gained. The effect of supplements fell with age and was larger in people already trained.

Per meal

The ISSN suggests about 0.25 g/kg of high-quality protein per meal, or 20 to 40 g, spread every three to four hours. In practice that is three or four meals with a palm-sized portion of protein each. The new US guidelines make the same point in plainer words: protein at every meal. On a GLP-1, eat it first.

Where the protein is

The 2025 to 2030 guidelines encourage a mix of animal and plant sources: eggs, poultry, seafood, red meat, beans, peas, lentils, nuts, seeds and soy. The joint GLP-1 advisory leans more towards plant sources, dairy, seafood, eggs and poultry, with red and processed meat in moderation because of their links to diabetes, heart disease and bowel cancer in population studies.

Is more protein safe?

For healthy kidneys, intakes in the ranges above are well studied. The joint advisory's caution is about long periods at 2 g/kg or more. If you have kidney disease, the target is a conversation with your clinician, not this page.

Tracking it

Protein is the one macro most people underestimate. A week of logging is usually enough to see where you are. Peptide AI's nutrition tracking shows protein against a daily target, and when it sits next to the training log and the body scanner, you can see whether intake and training are holding lean mass as weight comes down.