Cutting and bulking: sensible rates of loss and gain
Slow and steady wins on both sides: about 0.5 to 1% of body weight a week on a cut and 0.25 to 0.5% on a lean bulk. Here is why, and how to run each phase.
A cut is a planned period of eating below maintenance to lose fat. A bulk is a planned period of eating above it to support muscle gain. Both work best when they are moderate. Going too fast on a cut costs muscle and makes you miserable. Going too fast on a bulk mostly adds fat. This guide sets out sensible rates and how to judge them.
Start by knowing your real maintenance intake. If you have not worked it out yet, read maintenance calories first.
How fast to cut
For lifters who want to keep their muscle, a review of contest preparation for natural bodybuilders recommended losing about 0.5 to 1% of body weight a week [1]. For an 80 kg lifter, that is roughly 0.4 to 0.8 kg a week. The NHS gives similar general advice for weight loss: aim to lose 0.5 to 1 kg a week, steadily [2].
The case for going slowly comes partly from a study in athletes that compared weekly losses of about 0.7% and 1.4% of body weight. The slower group lost more fat (31% versus 21% of their fat mass) and gained a little lean mass, while the faster group's lean mass did not change [1].
Where you sit in that range is a judgement call. If keeping muscle is the priority, the slower end is the safer choice [1].
Keeping muscle in a deficit
A deficit makes building muscle harder. A meta-analysis found that resistance training in an energy deficit produced smaller lean mass gains than training without one, and that a deficit of around 500 kcal a day was enough to prevent lean mass gains altogether in the studies included [3]. Strength gains, however, were similar with or without a deficit [3].
The main levers for keeping muscle on a cut:
- Keep lifting heavy. Training is the signal to keep muscle. Keep training hard on your main heavy lifts. See progressive overload for the principles; on a cut, holding your strength is a good result.
- Eat plenty of protein. Higher intakes, around 2.3 to 3.1 g per kg of lean body mass a day, have been recommended for lean lifters in a deficit [1]. See protein for muscle.
- Do not rush. A moderate rate of loss, as above [1, 3].
How to bulk without getting fat
A review of off-season nutrition for bodybuilders suggested a surplus of about 10 to 20% above maintenance, aiming to gain about 0.25 to 0.5% of body weight a week for novice and intermediate lifters [4]. More advanced lifters, who can build muscle only slowly, were advised to be more conservative to avoid unnecessary fat gain [4]. For an 80 kg lifter, 0.25 to 0.5% is 0.2 to 0.4 kg a week.
| Phase | Weekly rate (% body weight) | Calories vs maintenance |
|---|---|---|
| Cut | about 0.5 to 1% loss [1] | below maintenance, adjusted to the trend |
| Lean bulk | about 0.25 to 0.5% gain [4] | about 10 to 20% above [4] |
Gaining faster than this mostly adds fat that you will need to diet off later. Check your rate against a weekly average, not daily readings, as explained in reading your weight trend.
Diet breaks and refeeds
A diet break is a planned period, often a week or two, of eating at maintenance during a long cut. A refeed is a shorter period, usually a day or two, of higher carbohydrate intake. The evidence for both is limited and mixed.
- In a 7-week trial in 27 resistance-trained people, two higher-carbohydrate days each week preserved more fat-free mass than continuous dieting, with similar fat loss in both groups [5].
- In a secondary analysis of the ICECAP trial, a 1-week diet break in resistance-trained athletes did not change fat mass, but it improved leg muscle endurance and was linked to better alertness and less hunger and irritability [6].
These are small, short studies. Diet breaks and refeeds are a reasonable tool if they help you stick to a long cut, but they are not essential, and they make a cut take longer overall.
When to end a cut
Plan an end point before you start, such as a target weight, a body fat estimate or a fixed number of weeks. Then stop, or take a break at maintenance, if:
- You have reached your goal.
- Your strength is falling steadily across several weeks, not just one bad session.
- Sleep, mood, sex drive or recovery are clearly suffering.
- You are thinking about food constantly or feel you are losing control around eating.
Eating too little for your training over long periods can harm both health and performance, in men as well as women. An International Olympic Committee consensus calls this relative energy deficiency in sport (REDs) [7]. If your periods stop or become irregular, you keep getting injured, or you feel persistently unwell, stop dieting and see your GP.
Avoid crash diets. The NHS notes that very low calorie diets are not suitable or safe for everyone and are usually only used when weight is affecting other health conditions [2]. If you have a history of disordered eating, please work with a doctor or dietitian rather than running a cut by numbers on your own.
Tracking it in ETS
Set your goal (cut, mild cut, maintain or lean bulk) on the Body tab and it sets calorie and macro targets from your maintenance estimate. Your weigh-in trend shows your actual rate in kg a week, and the weekly report helps you check it against your training, so you can see whether to adjust before a phase drifts off course.
Sources
- Helms ER, Aragon AA, Fitschen PJ. Evidence-based recommendations for natural bodybuilding contest preparation: nutrition and supplementation. Journal of the International Society of Sports Nutrition, 2014. Full text
- NHS. Obesity: treatment. NHS website. NHS
- Murphy C, Koehler K. Energy deficiency impairs resistance training gains in lean mass but not strength: a meta-analysis and meta-regression. Scandinavian Journal of Medicine and Science in Sports, 2022. Record
- Iraki J, Fitschen P, Espinar S, Helms E. Nutrition recommendations for bodybuilders in the off-season: a narrative review. Sports, 2019. MDPI
- Campbell, Aguilar, Colenso-Semple and colleagues. Intermittent energy restriction attenuates the loss of fat free mass in resistance trained individuals: a randomized controlled trial. Journal of Functional Morphology and Kinesiology, 2020. Solent University record
- ICECAP trial investigators. A 1-week diet break improves muscle endurance during an intermittent dieting regime in adult athletes: a pre-specified secondary analysis of the ICECAP trial. PLOS ONE, 2021. Record
- Mountjoy M, Ackerman KE, Bailey DM and colleagues. 2023 International Olympic Committee's (IOC) consensus statement on Relative Energy Deficiency in Sport (REDs). British Journal of Sports Medicine, 2023. Repository
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Last reviewed 7 October 2026. General information, not medical advice. Found a mistake? Email [email protected].