Body basics!

The ideal percentages of fat mass versus lean mass depend on gender, demographics and also the age of the individual, but the worldwide standards for minimum percent of body fat considered safe for good health is 5 percent for males and 12% for females. Around 3% of this fat is - visceral fat, which is the fat around organs, present for their protection and cushioning.
The average percentages, as per worldwide standards for adult body fat is almost to 15 to 18% for men and 22 to 25% for women.For the average Indian body, the fat percentages for Fitness are 21-24% for females, and14-17% for males, while it can be ‘Acceptable’ till 25-31% for females and 18-25% for males. A fat percentage of 32% plus for females and 25% plus puts the individual in overweight and obese categories.
These percentages are of prime importance for body-builders who train to keep the levels low, so that the definition and striations of each muscle are visible. Athletes also aim to keep it at the low end of this scale for improved results, however not at the cost of affecting their performance.
However, trying to keep the lean mass or fat mass percentages low by abusing the body through fasting or nutrient-intake restriction can have adverse effects not only the performance but also on health in general. Also, in case of extreme nutrient deficiency, our bones begin to contribute energy, and this usually leads to reduction in bone density, which again can lead to problems like brittle bones, fractures etc. Females who try to do this usually suffer from problems like irregular or no periods (amenorrhea)
The best way to lower fat percentages and keep higher lean mass percentages is by including weight training in a workout routine, rather than cutting the nutrient-intake drastically!