Diminishing returns
Across resistance-training trials, additional protein helped, but the average fat-free-mass benefit levelled off near 1.6 g/kg/day. About 1 g/lb sits closer to an upper “insurance” range than a universal minimum.
Based on an interview with Casey Butt ↗More protein,
The case for protein cycling
More protein,
all the time,
may not be better.
The Casey-inspired argument is not that protein is harmful. It is that keeping intake permanently high may offer diminishing returns while using calories that could support training through carbohydrate and adequate dietary fat.
49trials in a major resistance-training meta-analysis
1,863participants represented in that analysis
~1.6 g/kgestimated average intake beyond which added gains levelled off
Why vary intake?
A finite calorie budget should serve the whole programme.
Protein is essential. The question is whether the highest useful amount must be eaten every day, regardless of the training stimulus.
Protein is also fuel
When intake exceeds immediate needs, more amino acids can be oxidised and nitrogen excreted as urea. Small metabolic studies suggest habitual intake changes how the body handles protein, though this does not prove cycling builds more muscle.
Opportunity cost
Within a fixed calorie target, continually pushing protein higher leaves less room for carbohydrate and fat. Carbohydrate supports hard training; adequate fat supports health and keeps the diet workable.
The H/L/M logic
Different training days create different demands.
Heavy / Light / Medium training repeats the muscular stimulus without repeating the same joint, tendon and nervous-system stress. The dietary pattern follows that rhythm rather than resetting at midnight.
Read the Casey Butt interview, Part 2 ↗H
Heavy
Primary strength stimulus. High protein begins about two hours before training.
L
Light
Lower loading and joint stress. The surrounding phase is usually Normal.
M
Medium
A meaningful second stimulus. Another High window carries into recovery.
Evidence statusInteresting hypothesis.
Interesting hypothesis.
Unproven protocol.
The exact High / Normal / Low cycling pattern in this calculator does not appear to have been validated in large-scale human trials.
Evidence supports adequate daily protein and shows diminishing average returns at higher intakes. Small studies also show adaptation in amino-acid oxidation and protein turnover. But there is no convincing trial evidence that deliberately lowering protein “resensitises” muscle or that this precise weekly cycle produces more hypertrophy than a steady, adequate intake.
The calculator therefore presents Casey Butt’s proposed approach as an educational experiment—not an established best practice. It should not be used to diagnose, treat or prevent any condition.
Use at your own risk.If you have kidney disease, liver disease, are pregnant, are under 18, have an eating-disorder history, or have been given a therapeutic diet, speak with a qualified clinician before changing protein intake.
Shift the diet clock
around your training.
Enter your calories, body composition and actual Heavy / Light / Medium session times.
Open the calculator →