^ Jump up to: a b c Schwingshackl, L; Boeing, H; Stelmach-Mardas, M; Gottschald, M; Dietrich, S; Hoffmann, G; Chaimani, A (2017). "Dietary Supplements and Risk of Cause-Specific Death, Cardiovascular Disease, and Cancer: A Systematic Review and Meta-Analysis of Primary Prevention Trials". Advances in Nutrition: An International Review Journal. 8 (1): 27–39. doi:10.3945/an.116.013516. PMC 5227980. PMID 28096125.
A 55-year-old woman who gets less than 30 minutes of daily physical activity should eat five ounces of grains; two cups of vegetables; one and a half cups of fruit; three cups of milk; five ounces of meat and beans; five teaspoons of oils, and no more than 130 calories of additional fat and sugar. If she got 30 to 60 minutes of daily exercise, she could increase her intake to six ounces of grains; two and a half cups of vegetables; and up to 265 additional calories of fat and sugar.
It's trendy to think "food should be fuel" or that food is something that helps you lose (or, ahem, gain) weight. But thinking only in terms of number on the scale takes away a huge part of what eating is about: pleasure. "If you think of eating as something enjoyable and something you do without guilt or without judging yourself, and you stay active, you're less likely to overeat, have a better diet, and maintain any weight loss for the long haul," says Zied. It's true: feeling guilty about your food choices can undermine weight loss—and even pack on the pounds—while a celebratory mindset gives you more control over your diet and can thwart weight gain, found a 2014 study in the journal Appetite.
Processing of food reduces its nutritional content, and the finished products are often based on fractions of the original foods. One example is milling grain to make white flour,  which has a lower nutritional density than whole grain flour. The reduction in nutritional value has accelerated since whole foods are now divided into pieces, for example, boneless chicken breast. When meat is injected with saline to increase the volume, the relative level of essential nutrients is reduced. In the United States, many supermarkets in low-income rural and inner city areas have a limited selection of nutrient-dense foods, compared with high-income areas. 
Carbohydrates should provide 45%–65% of your daily calories. Most of those calories should come from the complex carbohydrates in high-fiber and unrefined foods, such as bran cereal and other whole-grain products, brown rice, beans and other legumes, and many fruits and vegetables. These carbohydrates are digested and absorbed slowly, so they raise the blood sugar gradually and don't trigger a large release of insulin. People who eat lots of these foods have higher HDL ("good") cholesterol levels and a lower risk of obesity, diabetes, and heart disease. A good amount of soluble fiber in the diet lowers LDL ("bad") cholesterol, and high-fiber diets reduce the risk of intestinal disorders ranging from constipation and diverticulosis to hemorrhoids. Some studies have shown that fiber may help reduce the risk of colon cancer. Men need more fiber than women: 38 vs. 25 grams a day before the age of 50 and 30 vs. 21 grams a day thereafter.