Potatoes often get a bad rap, but when it comes to weight loss they're hard-to-beat sources of scale-dropping fiber. According to the Cleveland Clinic, sweet potatoes will up the insoluble fiber in your diet, keep you full longer, and you can bake and eat one for just 114 calories. Just watch what you load it with — instead of cheese or sour cream, opt for good-for-you fillings like black beans, tomatoes, and bell peppers. A study in the journal Metabolism found that eating half a grapefruit before meals may help reduce visceral fat and lower cholesterol levels. Participants in the 6-week study who ate a Rio Red grapefruit fifteen minutes before each meal saw their waists shrink by up to an inch, and LDL levels drop by 18 points. Though researchers don’t exactly know what makes grapefruit so good at burning fat, they attribute the effects to a combination of phytochemicals and vitamin C found in the tart treat. For people who are healthy, a healthy diet is not complicated and contains mostly fruits, vegetables, and whole grains, and includes little to no processed food and sweetened beverages. The requirements for a healthy diet can be met from a variety of plant-based and animal-based foods, although a non-animal source of vitamin B12 is needed for those following a vegan diet. Various nutrition guides are published by medical and governmental institutions to educate individuals on what they should be eating to be healthy. Nutrition facts labels are also mandatory in some countries to allow consumers to choose between foods based on the components relevant to health. These support bone health and have other possible benefits. Dairy products are the best sources of calcium, but you can also get it from fortified foods as well as canned salmon, sardines, dark leafy greens, and most tofu. If you can’t get the recommended 1,000 to 1,200 milligrams a day from food, take a calcium supplement. It’s hard to consume enough vitamin D from foods (the RDA is 600 to 800 IU a day, though other experts advise more). Thus, many people—especially those who are over 60, live at northern latitudes, or have darker skin—should consider taking a supplement.