The reason why the body fat rate of boys is lower than that of girls is mainly determined by women's genes. Because women need some fat as a guarantee of fertility, under the action of estrogen, the body fat rate of normal women is usually 18%-25%, while the proportion of men's muscles is higher and their basal metabolism is greater, so the proportion of fat is smaller.
Is the 20-year-old boy's body fat rate high? Usually, the standard body fat rate for men is 10-20%. Although 20% is within this reasonable range, if you want to be in good shape, you still need to be lower.
The harm of low body fat rate in boys will greatly affect the absorption of vitamins, especially fat-soluble vitamins. Without fat carrier, the body's hormone secretion will also have problems. Therefore, the body fat rate must also be within the normal range.