Protein intake

One card per question: one outcome, in one group of people.

10 results: 10 published, 0 pending reviewLast reviewed 26 Oct 2026Data current as of 25 Oct 2026

How to read this page

Each card is one question: what happened to one outcome, in one group of people, when the intervention was compared with the alternative named on the card.
The bars show how sure we are, not how big the effect is. A large effect from weak studies still gets few bars.
The numbers are always there. Open a card to see the studies behind it and the sentence in each paper that a number was read from.

High. We are very confident the real effect is close to what the studies found.
Moderate. The real effect is probably close to what the studies found.
Low. The real effect may be quite different from what the studies found.
Very low. The evidence is very uncertain.
Insufficient. A reviewer found too little evidence to say anything about the effect.
Pending review. Not rated yet. The numbers and sources are shown; a named reviewer still has to rate how sure we can be.

Protein intake: one line per result, with certainty, effect, studies and participants. Open a line to see where it comes from.
Outcome	How sure are we?	Effect	Studies	Participants
Higher vs lower daily protein intake during resistance training
Body fat Adults with resistance training · Higher vs lower protein intake	High	Lower	–studies	–participants
Lean mass Adults with resistance training · Higher vs lower protein intake	High	Higher	72studies	2,686participants
Maximum strength Adults with resistance training · Higher vs lower protein intake	High	Higher	28studies	–participants
Lower-body strength Adults with resistance training · Higher vs lower protein intake	Moderate	Higher	–studies	–participants
Muscle fibre size Adults with resistance training · Higher vs lower protein intake	Moderate	Higher	–studies	–participants
Muscle size Adults with resistance training · Higher vs lower protein intake	Moderate	Higher	–studies	–participants
Protein supplementation in older adults
Lower-body strength Older adults with resistance training · Protein supplementation vs control	Moderate	Medium difference	–studies	–participants
Lean mass Older adults · Protein supplementation vs control	Low	No clear difference	–studies	–participants
Lean mass Older adults with resistance training · Protein supplementation vs control	Low	Higher	–studies	–participants
Lower-body strength Older adults · Protein supplementation vs control	Low	No clear difference	–studies	–participants

“No clear difference” does not mean “no effect”: the studies may simply be too small to tell.

Loading the grid…

Protein intake: one line per result, with certainty, effect, studies and participants. Open a line to see where it comes from.
Outcome	How sure are we?	Effect	Studies	Participants
Higher vs lower daily protein intake during resistance training
Body fat Adults with resistance training · Higher vs lower protein intake	High	Lower	–studies	–participants
Lean mass Adults with resistance training · Higher vs lower protein intake	High	Higher	72studies	2,686participants
Maximum strength Adults with resistance training · Higher vs lower protein intake	High	Higher	28studies	–participants
Lower-body strength Adults with resistance training · Higher vs lower protein intake	Moderate	Higher	–studies	–participants
Muscle fibre size Adults with resistance training · Higher vs lower protein intake	Moderate	Higher	–studies	–participants
Muscle size Adults with resistance training · Higher vs lower protein intake	Moderate	Higher	–studies	–participants
Protein supplementation in older adults
Lower-body strength Older adults with resistance training · Protein supplementation vs control	Moderate	Medium difference	–studies	–participants
Lean mass Older adults · Protein supplementation vs control	Low	No clear difference	–studies	–participants
Lean mass Older adults with resistance training · Protein supplementation vs control	Low	Higher	–studies	–participants
Lower-body strength Older adults · Protein supplementation vs control	Low	No clear difference	–studies	–participants

Higher vs lower daily protein intake during resistance training

Body fat Adults with resistance training · Higher vs lower protein intake

High

Lower

–

Lean mass Adults with resistance training · Higher vs lower protein intake

High

Higher

2,686

Maximum strength Adults with resistance training · Higher vs lower protein intake

High

Higher

–

Lower-body strength Adults with resistance training · Higher vs lower protein intake

Moderate

Higher

–

Muscle fibre size Adults with resistance training · Higher vs lower protein intake

Moderate

Higher

–

Muscle size Adults with resistance training · Higher vs lower protein intake

Moderate

Higher

–

Protein supplementation in older adults

Lower-body strength Older adults with resistance training · Protein supplementation vs control

Moderate

Medium difference

–

Lean mass Older adults · Protein supplementation vs control

Low

No clear difference

–

Lean mass Older adults with resistance training · Protein supplementation vs control

Low

Higher

–

Lower-body strength Older adults · Protein supplementation vs control

Low

No clear difference

–