Skinny fat: when BMI is normal but the body is not
The doctor says “your weight is normal,” your friends are jealous, but in the mirror there is a soft belly, flabby arms, and no shape at all. Fatigue by lunchtime, cold hands, fasting blood sugar 5,8. This is not “your constitution” and not “normal for your age.” It is being thin on the outside and fat on the inside: 33-38% body fat at a BMI of 21-23, with little muscle. Section — fat and muscle.
Where it comes from
Every diet without strength training takes up to 25-30% of body weight from muscle. The weight comes back as fat. Five diets in ten years — and at the same weight, the body has been rebuilt: it used to have 24 kg of muscle and 16 kg of fat, now it has 18 and 22. Add sedentary work, years without exercise, and after 40 — falling estrogen levels. None of these changes are visible on the scales, so a woman is sure she is “maintaining her weight,” while in reality she was losing her body. About muscle as an engine — muscle and energy expenditure.
BMI 22
and 35% body fat
25-30%
diet losses — muscle
higher
diabetes risk compared with muscular people with obesity
weight 0
change during the first months
Why it is dangerous
In such women, fat is more often visceral, while there is little muscle — the main consumer of glucose. The result: insulin resistance and prediabetes at a normal weight, which no one looks for because she is “thin.” The medical term is metabolically unhealthy normal weight; such people make up 20-30% of those with a normal BMI, and their risk of heart disease is higher than that of people with obesity and good test results. About fat around the organs — visceral fat.
Why a deficit makes things worse
Another diet means another two kilos of muscle lost. Weight 58, then 60, then 57, while body fat keeps increasing. The only thing that changes the picture is progressive strength training and 1,6 g/kg of protein. Not a deficit: calories at maintenance, a low-carbohydrate plate, a 14/10 eating window at most. Weight stays the same or rises by a kilogram during the first months — this is muscle and water in the muscles — while the waist, arms, and posture change. After six months, at the same weight, it is a different body. This is body recomposition.
What to do
Stop trying to lose weight
Calories at maintenance. A deficit is the number-one enemy in this situation.
1,6 g/kg of protein
At a weight of 58 — 90-95 g per day. Three meals with 30 g each. Without this, you cannot build muscle.
Strength training 3 times a week
Squats, deadlifts, presses, and rows with progressive overload. Dumbbells at home or the gym. Not cardio.
Put the scales away for three months
Measure your waist, upper arm, thigh, strength in your sets, and take photos. The scales will lie in both directions.
Sleep and sugar
7-8 hours, without sugar and flour. Insulin and cortisol are what keep fat on the belly.
Frequently asked questions
I do not want to “bulk up.”
It will not happen: women have 15-20 times less testosterone. Three strength-training sessions a week for a year will give you a toned body, not bodybuilding.
My weight increased by 1,5 kg after starting strength training — is it fat?
Water in the muscles and glycogen. It will stabilize after a month. Watch your waist — if it is getting smaller, everything is going right.
How long should I wait?
You will feel stronger after 4 weeks, see your shape in photos after 3 months, and have a different body after 6-12.
Reviewed by Anastasia Zhukova, Fitness Trainer • Author of a Nutrition and Training System • Creator of an AI Personal Support Platform
A human has reviewed this material against the method and real client practice.