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Food provides nutrients from six broad classes: proteins, fats, carbohydrates, vitamins, dietary minerals, and water. Carbohydrates are metabolized to provide energy. Proteins provide amino acids, which are required for cell construction, especially for the construction of muscle cells. Essential fatty acids are required for brain and cell membrane construction. Vitamins and trace minerals helps to keep good electrolyte balance and are used for metabolic processes. Dietary fiber also affects one's health, although it's not digested into the body. The National Academy of Sciences and the World Health Organization publish guidelines for dietary intakes of all known essential nutrients. Sometimes dieters will ingest excessive amounts of vitamin and mineral supplements. While this is usually harmless, some nutrients are dangerous. Men (and women who don't menstruate) need to be wary of iron poisoning.[citation needed] Retinol (oil-soluble vitamin A) is toxic in large doses. Vitamin E supplements have been found in some studies to increase mortality, congenital heart defects in offspring and an increased risk of stroke (see the corresponding article).[citation needed] Most people can obtain their nutritional needs from their diet. In any event, a multivitamin taken once a day will suffice for the majority of the population. Weight loss diets that manipulate the proportion of macronutrients (low-fat, low-carbohydrate, etc.) have not been shown to be any more effective than diets that maintain a typical mix of foods with smaller portions and perhaps some substitutions (e.g. low-fat milk, or less salad dressing).[23] Extreme diets may, in some cases, lead to malnutrition. Besides the importance of eating a balanced diet that includes all the necessary nutrients, other factors also contribute to healthy nutrition. As well, drinking sufficient amounts of water is often claimed to help eliminate toxins and fat.[citation needed] Heavily processed and fried foods as well as sweets, junk foods, and alcohol should also be avoided in a healthy diet.[24] Also a topic of great importance discussed among nutritionists as well as psychologists is the attitude to weight-loss and the consumption of food in general. Voicing ideas such as "it's just one burger" during and after weight loss regimes is discouraged, and often is said on the part of an insecure individual who has reached the unfortunate conclusion that nothing can be done any longer and that any effort to do so is futile. The advice given is, avoid reaching such a conclusion, as not only does it change one's perception of the effect of excessive amounts of food on the body, but also encourages a 'lacklustre' lifestyle and approach to life as a whole. Nutritionists also agree on the importance of avoiding fats, especially saturated fats, to reduce weight and to be healthier. They also agree on the importance of reducing salt intake because commercial foods such as snacks, biscuits, and bread, among others, already contain salt, thus contributing to an excess of salt daily intake.[25] MyPyramid Food Guidance System is the result of extensive research performed by the United States Department of Agriculture to revise the original Food Guide Pyramid. It offers a wide array of personalized options to help individuals make healthy food choices. It also provides advice on physical activity.[26] |
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