Cutting Macros for a 140 lb Male (Keto)

A practical starting target is 2111 calories/day — a 373-calorie deficit below your estimated TDEE of 2484. This provides a meaningful signal for fat loss without being aggressive enough to risk significant muscle loss or excessive fat gain. Adjust in 100-calorie steps after 2–3 weeks of data.

At 140 lb, a daily target of 140gm of protein (1.00g per lb bodyweight) supports body composition goals whether cutting, building, or maintaining. Protein has a higher thermic effect than carbs or fats, keeps hunger lower than either, and directly determines how much muscle your body can build or retain. Distribute across 3–5 meals for best use — a single large protein serving has diminishing returns compared to spread intake.

Muscle loss risk on a 373-calorie deficit is real but manageable. The most important protection is keeping protein at 140gm/day — elevated protein directly reduces muscle breakdown during a deficit. Continuing resistance training is the second most important factor; muscle is only retained if it is being used. A 373-calorie deficit is in a moderate range, which means weekly fat loss should be around 0.1 lbs — sustainable without requiring the body to cannibalize significant lean tissue.

On a ketogenic approach at 140 lb, net carbs are capped at approximately 18gm/day to maintain ketosis. Fat provides the majority of calories at 164gm/day (roughly 70% of total intake). Protein stays moderate at 140gm — high enough to protect muscle but not so high that excess amino acids convert to glucose via gluconeogenesis and interrupt ketosis. Focus on tracking net carbs (total carbs minus fiber) rather than total carbs.

At 140 lb, total calorie targets are lower, which means every macro gram matters more. Protein is the priority to protect — at 140gm, you are targeting 1.00g per lb, which leaves little room to reduce protein without consequences for muscle retention. If you need to reduce total calories, trim from carbs or fats, not protein. The lower absolute calorie target also means tracking accuracy is more important: a 200-calorie tracking error represents a larger percentage of total intake at 2111 calories than it would at 2,800+.