Nowadays, overweight problems are directly threatening health. there have been 2/3 of adults and 1/3 of children ether over weight or obsess in U.S. over the 40years (Mantel 2010). Obviously, the overweight issues are like a bomb that shortening American’s life as it related with so many diseases, such as heart disease, cancers, stroke, etc. In addition, some of American’s sedentary lifestyle more likely to lead people to obesity-associated diseases caused by eating large portion size of food, having lack of exercises, plus high stress in the course of life. Therefore, diet become critical since it is the way that can improve quality of people’s life. The question is how diets can impact on our quality of life.

Currently, there are tremendous diet plans actively promoted on the market, they all claimed that they are effective to help people losing weight: such as vegetarian diets, Semi-vegetarian diets, Weight control diets, Low-calorie diets, Very low calorie diets, Low-fat diets, Crash diets, Detox diets, Diets followed for medical reasons, and the other diets; well know Low-carbohydrate diets. How can we choose the right plan from thousands of them? The fact shows that it is not an easy task since the human body is complicated due to our unique genes. Some of diet plans actually are harmful and damaging to certain type of people‘s health for the long run.
Based on Leonard, statistic data show that, The standard American diet is heavy in saturated fats, partially hydrogenated oils, refined carbohydrates, and highly processed foods, this diet, in combination with a sedentary lifestyle, large portion sizes, and high stress is blamed for the increase in obesity and associated diseases in the U.S.

People taking the more combination of vegetables and fruit can lower the risk of getting cardiovascular disease and stroke, due to human body need certain level of