How to Get to 10% Body Fat (and Is It Worth It?)

How to get to 10% body fat: work out your target

1. Estimate your body fat with one consistent method.
2. Lean mass = body weight × (1 − body fat as a decimal).
3. Target weight = lean mass ÷ 0.9.
4. Weight to lose = current weight − target weight.

This assumes all the weight you lose is fat, which is never quite true, so the real target is usually a little lower. Here it is for an 80 kg (176 lb) man:

Starting body fat	Lean mass	Target weight at 10%	Weight to lose
15%	68 kg (150 lb)	about 75.6 kg (167 lb)	about 4.4 kg (10 lb)
20%	64 kg (141 lb)	about 71.1 kg (157 lb)	about 8.9 kg (20 lb)
25%	60 kg (132 lb)	about 66.7 kg (147 lb)	about 13.3 kg (29 lb)

How long does it take?

In their 2014 evidence-based recommendations for natural bodybuilders, Helms and colleagues advise losing about 0.5 to 1% of your body weight a week, and warn that "the leaner the competitor becomes the greater the risk" of losing lean mass. For someone getting down towards 10%, that means staying at the slower end, especially for the last few kilograms.

For the 80 kg man, 0.5% to 0.75% a week is about 0.4 to 0.6 kg (0.9 to 1.3 lb):

Starting body fat	At 0.6 kg (1.3 lb) a week	At 0.4 kg (0.9 lb) a week
15%	about 7 weeks	about 11 weeks
20%	about 15 weeks	about 22 weeks
25%	about 22 weeks	about 33 weeks

Then add slack. Loss slows as you get lighter, and holidays, illness and busy weeks happen. If the answer is longer than you hoped, split it into two cuts with a few weeks at maintenance between them. How long should a cut last? shows how to plan the timeline, including planned breaks at maintenance.

The plan that gets you there

None of this is special to 10%. It is a well-run cut, done patiently:

• Calories: set them for your chosen rate. Helms and colleagues note that a deficit of about 500 calories a day theoretically loses about 0.45 kg (1 lb) of fat a week. The calorie and macro calculator gives you a starting point.
• Protein: about 1.6 to 2.2 g per kg of body weight a day, towards the top as you get leaner. Helms and colleagues suggest 2.3 to 3.1 g per kg of lean mass for lean lifters dieting hard.
• Fat: about 15 to 30% of calories (Helms and colleagues); carbohydrate makes up the rest and fuels your training.
• Training: keep lifting heavy and try to hold your strength. This is the signal that tells your body to keep its muscle.
• Steps: set a daily target and keep it steady, so your everyday movement does not quietly drop.
• Tracking: weigh every morning, judge the weekly average and adjust every two to three weeks, one small change at a time.

Macros for cutting walks through the numbers in full.

What it costs

There is little research on how men feel at 10% specifically. What is clear is that the costs rise the leaner you go:

• Hunger and food focus. Expect the last stretch to be hungrier than the start, and to plan meals out and social events more carefully.
• Training. Late in a cut, the goal is holding your strength, not setting records.
• Hormones and strength, at the extreme. In a 2013 case study by Rossow and colleagues, a natural bodybuilder dieted from 14.8% to 4.5% body fat. His testosterone fell by about three quarters and his mood worsened, then both recovered after the show; his strength had still not fully recovered six months later. That is far leaner than 10%, but it shows the direction of travel.
• Rebound risk. In a 2017 pilot study (Trexler and colleagues), lean physique competitors' average fat mass rose from about 7.7 kg to 10.0 kg (17 to 22 lb) within four to six weeks of their shows. A 2012 review by Dulloo and colleagues argues that lean people may be especially prone to regaining more fat than they lost after hard diets, though that idea still needs more testing.

If your sex drive, mood or sleep fall away, if you feel unwell, or if food starts taking over your thoughts, stop the cut and speak to your doctor or GP.

Can you stay at 10%?

Whether you can stay there varies from person to person, and there is little research to say who can. Reaching it for a holiday or a photoshoot is a different project from living there all year. The honest test is whether you can hold it with food you enjoy, a normal social life and training that is still going well.

If not, settling a little higher is a perfectly good result. How to stay lean after a cut covers choosing a weight you can keep and how to hold it.

Is it worth it?

It is worth it if you want to see what you look like lean, you have a plan for afterwards, and the timeline fits your life. It is probably not worth it if you are hoping it will fix how you feel about your body, if your training and sleep are already a mess, or if dieting has caused you problems in the past. In that last case, speak to your GP before you start.

How coaching helps

Getting to 10% is a long cut, and the last few weeks are where people stall, lose strength or give up. With one-to-one coaching from CoachAk, your training program and calorie, macro and step targets are set in the app, and you log your weight every day and every workout, with personal bests tracked. Your weekly check-in takes about three minutes and covers your weight, training and nutrition adherence, steps, sleep, energy, hunger and stress, with optional body measurements and photos. Your coach replies with written feedback, adjusts your plan as you get leaner, and helps you decide when to push on, take a break or stop.

If you want to get lean properly and keep your muscle, apply for coaching.