The body fat index is an estimated range of what a person's body fat percentage should naturally be. Normally our body fat percentage never stays the same, there will be slight variations from week to week or each month. this is because our bodies adapt to various natural and subtle changes in lifestyles and eating habits.

Men and women have a different body fat index, with women's naturally being much higher than men. This may be mostly due to the sex hormones, women have higher levels of oestrogen necessary for reproductive functions, and men have much higher testosterone levels, which help give males more muscle mass.

Body Fat index and Age

As we age past 30 years body fat percentage naturally rises often due to hormonal changes, sometimes referred to as "middle age spread".

For men, there is a gradual decline in testosterone levels which slowly reduces the amount of lean muscle weight. This decreases the metabolism and the body requires less energy to maintain weight. Along with eating habits strongly established it all contributes a positive energy balance forcing the body to store excess energy in fat cells.

Average Body Fat Index for Men & Women in percentage

Values are estimated and can be plus or minus 5 percent to give a range for the body fat index.