Protein at 1.2 to 1.6 g/kg: what the evidence supports

The 2025 to 2030 US Dietary Guidelines, released in January 2026, recommend 1.2 to 1.6 grams of protein per kilogram of body weight a day, a 50 to 100% increase over the previous minimum, according to Harvard’s Nutrition Source. The evidence for that range is strongest in one specific setting: adults doing resistance training, where a 49-trial meta-analysis found gains levelling off around 1.62 g/kg a day.

What do the new guidelines say about protein?

The guidelines also name “highly processed foods” for the first time.

Harvard’s analysis of the guidelines raises two points. The protein increase does not distinguish between sources, even though plant proteins and fish are associated with more favourable health outcomes than diets high in red meat. And the guidelines’ food pyramid conflicts with their own saturated fat limit: three full-fat dairy servings plus a tablespoon of butter reach about 24 g of saturated fat, above the 22 g cap for a 2,000-calorie diet, before any other food is eaten.

Demand for protein is visible in search and shopping data. Glimpse’s trend data show “high protein dessert” up 76% and “high protein yogurt” up 46% year over year as of January 2026, and NielsenIQ reports that households using GLP-1 medicines drove 43% of sales growth in muscle health products. Related: see how much of GLP-1 weight loss is muscle.

Who does the evidence for higher protein intake apply to?

The best-known trial data come from people doing resistance training. A meta-analysis of 49 randomised trials with 1,863 participants (Morton et al., British Journal of Sports Medicine, 2018) found that protein supplementation added a small but statistically significant gain in fat-free mass beyond training alone, roughly 0.30 kg. The gains levelled off at about 1.62 g/kg a day, with a 95% confidence interval extending to about 2.2 g/kg. Intakes above that added no measurable benefit in the pooled data. Older participants showed relatively smaller responses.

Two things follow. First, the effect size is modest: a fraction of a kilogram over a training programme. Second, the trials tested trained adults, so the guideline range should not be read as a proven target for everyone. How much protein a given person needs depends on age, activity, kidney function and medications, which is a conversation for a clinician.

The bottom line

• The 2025 to 2030 US Dietary Guidelines recommend 1.2 to 1.6 g/kg a day, a 50 to 100% increase over the earlier minimum.
• In 49 trials (1,863 participants) of resistance training, protein supplementation added about 0.30 kg of fat-free mass, plateauing near 1.62 g/kg a day.
• Harvard notes the guidelines do not separate protein sources, and the evidence is strongest for trained adults, less so for others.