The foods you choose to eat can have a direct impact on your ability to enjoy life to its fullest. Perhaps the most apparent positive effect of food is the pleasurable feeling you get from eating a good-tasting meal. It might be a plate of grilled chicken, corn-on-the-cob, fresh vine-ripened tomatoes, and a baked potato, or a steaming dish of spaghetti topped with a zesty tomato sauce.Your diet can have long-term effects on your health as well. Diet plays a major role in promoting and maintaining good health, avoiding some chronic diseases and treating others, and speeding recovery from injuries. In earlier times, diseases such as goiter and pellagra were relatively common-both are caused by nutritional deficiencies and cured by diets containing sufficient amounts of a particular nutrient. In the case of goiter, iodine is the missing nutrient; with pellagra it is mainly niacin, a B vitamin. These diseases are rare today in the United States because most Americans get enough of these essential nutrients in their diets.Although it is unlikely that you or your family will ever suffer from an illness caused by pronounced dietary deficiency, the foods you eat can exert more subtle and, in the long run, no less harmful effects on your health. During the past few decades, scientists have discovered several nutritional factors that play important roles in the development of specific diseases. Diet plans rich in certain types of fat, for example, may actually improve the risk of establishing coronary heart disease and certain malignancies, and, among prone people, too much salt in your meals are believed to improve the likelihood of developing hypertonie (high blood pressure). Other scientific proof shows that the current average American diet-which is high in fatty foods and lower in fruits and vegetables-can improve the danger of developing certain varieties of cancer, especially cancers of the esophagus, colon (large bowel), prostate, and breast. Certain nutritional patterns can improve the likelihood of oral caries (cavities). Additionally, habitually eating more calories than your body uses for maintenance and physical activity produces obesity and boosts the risk of several chronic diseases including noninsulin-dependent diabetes mellitus, a form of diabetes that will not usually require daily insulin injections but has many undesirable issues and generally appears after age group 40.As the body of research on diet-disease cable connections has grown in the last half century, researchers, policymakers, officials of the food industry, consumer groups, and others have involved in a argument about how precisely much and exactly what kind of proof justifies giving nutritional advice to the general public. They have also argued about how precisely best to control danger factors where there is general contract among scientists.The particular core problem in this debate is the one which characterizes all science: absolute evidence is difficult to obtain. This is particularly true in a science such as nutrition, in which many factors-age, sex, genetics, interpersonal behavior, and ethnic differences, for example-can play a role in what food we eat and how it influences our bodies.