How to eat not fat may be caused by metabolic factors, genetic factors, dietary structure, disease factors and other reasons. 1. Metabolic factors: everyone’s metabolic level is different, compared to the high metabolic rate of the population is not easy to diet and fat, mainly due to the metabolism of the large amount of fat consumption will be more, it is not easy to get fat. 2. Genetic factors: genes determine that some people have more brown adipose tissue, this part of the fat is easier to convert into heat, therefore, fat is not easy to be deposited in the body. Genes also partially determine the digestive and absorption function, appetite size, and so on. 3. Dietary structure: How to eat not fat may be the intake of high-calorie food is relatively small, so that excess calories will not be consumed in a timely manner and will not be converted into fat, therefore, not easy to eat fat. Singed disease factors: such as malignant tumors, tuberculosis and other consumptive diseases. Diabetic patients may also show that they eat a lot but are thin. Hyperthyroidism patients may also eat a lot, thin, sweating and other manifestations. How can not eat fat need to consider whether it is due to disease, if you suspect that it is caused by disease, you should go to the hospital in time to avoid adverse effects.