Diets to promote weight loss are divided into four categories: low-fat, low-carbohydrate, low-calorie, and very low calorie. A meta-analysis of six randomized controlled trials found no difference between the main diet types (low calorie, low carbohydrate, and low fat), with a 2–4 kilogram weight loss in all studies. At two years, all of the diets in the studies that reduced calories caused equal weight loss regardless of whether changes in fat or carbohydrate consumption were emphasized.
Is there anything avocados can't do? This creamy superfood (loaded with monounsaturated fats, potassium, magnesium, folate, and vitamins C and E) has been linked to improved vision, good heart health, and a reduced risk of certain cancers. And avocados can also help whittle your middle: according to one study, people who regularly consume them weigh less and have smaller waists than those who do not. Another study found that women who eat half an avocado at lunchtime might experience reduced food cravings later in the day.
Another weight-loss-friendly substitute to keep in mind is favoring salsa over ketchup. While ketchup typically has around 19 calories and 4 grams of sugar per tablespoon, fresh tomato salsa has about 5 calories per tablespoon, no added sugar, and is packed with nutritious veggies. Tomatoes, for example, are loaded with fat-blasting fiber and vitamin C, a deficiency of which Arizona State University researchers associated with increased body fat and larger waists. If you can handle spice, toss some jalapenos in your salsa to rev up your metabolism. For more on how you can switch your metabolism into overdrive, check out the best ways to boost your metabolism!
Drinking enough water can help you stay slim, too. Research from the American Chemical Society in Boston found that having two 8-ounce glasses of water before a meal while also reducing portion sizes could help you lose weight and keep it off. Not to mention, water fills you up, curbing your appetite: "In addition to slightly boosting your metabolism, drinking water before meals has been shown to help you eat less without trying," says Sass.
For a 2,000-calorie daily diet, aim for 2½ cups of vegetables and 2 cups of fruit a day. If you consume more calories, aim for more produce; if you consume fewer calories, you can eat less. Include green, orange, red, blue/purple, and yellow vegetables and fruits. In addition to the fiber, the nutrients and phytochemicals in these foods may help protect against certain types of cancer and other diseases. Legumes, rich in fiber, can count as vegetables (though they have more calories than most vegetables). For more fiber, choose whole fruits over juice.