Essential Body Fat vs Storage Body Fat
The two types of body fat, why one is vital for survival and the other is not, and how they differ.
Quick Answer
Essential body fat is the minimum fat your body needs to survive. It protects organs, insulates nerves, and enables hormone production. Men need 2-5%, women need 10-13%.
Storage body fat is extra energy stored under the skin and around organs. This is the fat that increases or decreases when you gain or lose weight. It can be safely reduced through diet and exercise.
What Is Essential Body Fat?
Essential body fat is the fat your body cannot function without. It is found in organs, bone marrow, the central nervous system, and cell membranes throughout the body. Without it, basic physiological processes break down.
Essential fat serves several critical functions: it cushions and insulates vital organs, provides structure for every cell membrane in the body, insulates nerve fibers for proper signal transmission, and enables the production of hormones like estrogen, leptin, and adiponectin.
The American Council on Exercise (ACE) classifies essential fat as 2-5% of total body weight for men and 10-13% for women[1]. Women require significantly more essential fat due to the biological demands of reproductive function, breast tissue, and hormonal regulation. This difference is why healthy body fat ranges are always higher for women than for men.
What Is Storage Body Fat?
Storage body fat is additional fat your body accumulates as an energy reserve. When you eat more calories than you burn, the excess is converted to storage fat. When you eat less than you burn, your body draws on storage fat for energy.
Storage fat exists in two forms. Subcutaneous fat sits directly under the skin and is the fat you can pinch. Visceral fat wraps around internal organs in the abdominal cavity and is linked to higher risk of heart disease, type 2 diabetes, and other metabolic conditions. Both are types of storage fat, but visceral fat carries greater health risks.
Key Differences
| Essential Fat | Storage Fat | |
|---|---|---|
| Purpose | Survival. Protects organs, insulates nerves, enables hormones. | Energy reserve. Fuel for when caloric intake is low. |
| Location | Organs, bone marrow, nervous system, cell membranes. | Under the skin (subcutaneous) and around organs (visceral). |
| Men | 2-5% of body weight | Varies. Everything above essential fat. |
| Women | 10-13% of body weight | Varies. Everything above essential fat. |
| Can you lose it? | No. Losing it causes organ failure and death. | Yes. Reduced through caloric deficit and exercise. |
| Health risk if too low | Fatal. Hormonal collapse, organ damage. | Minimal. Lower storage fat generally improves health. |
Test Your Knowledge
Explain the difference between essential body fat and storage body fat.
Which of the following is NOT true about essential body fat?
Frequently Asked Questions
Sources
- [1]American Council on Exercise (ACE). ACE Personal Trainer Manual. ACE, San Diego, CA.
Related Resources
- Body fat percentage calculator — Find out your total body fat percentage.
- Body fat percentage chart — See ACE categories from essential fat to obese.
- Body fat percentage for men — Why men need 2-5% essential fat.
- Body fat percentage for women — Why women need 10-13% essential fat.
- Body fat percentage records — What happens when essential fat drops to near zero.