Scientists have found from the research that two parts of human genes are mainly responsible for sending instructions to fibers on human cell membranes, thus controlling how much food cells convert into heat. For example, they function like faucets. Once the genetic structure changes between generations, it will lead to too many or too few fat cells in the human body. As a result, people are classified as obese or thin at birth, and what scientists do is to find out how to keep genes stable. This is a healthy and effective weight loss method popular in the new century.