Not all the nutrients and other substances that contribute to good health have been identified, so eating a wide assortment of healthy whole foods like fruits and vegetables helps ensure that you get all of the health-promoting benefits that foods can offer. If your diet, day after day, consists of the same half dozen foods, it could fall short. In addition, varying your food choices will limit your exposure to any pesticides or toxic substances that might be present in particular foods. 

A fat-burning superfood, grapefruit contains a compound that can lower the fat-storage hormone insulin, which in turn can lead to weight loss. In fact, eating half a grapefruit before each meal could help you lose up to a pound a week—even if you don't change anything else about your diet. Because grapefruits are 90% water, which fills you up, they also act as a natural appetite suppressant.

Although white potatoes offer some potassium and fiber, sweet potatoes reign supreme in the nutrition department, meaning you should consider adding sweet potatoes to your diet. A large sweet potato contains around 4 grams of satiety-boosting protein, 25 percent of the day’s belly-filling fiber, and 11 times the recommended daily intake of vitamin A. What’s more? It’s less than 200 calories.
Kamut is an ancient grain native to the Middle East that is an excellent source of heart-healthy omega-3 fatty acids, protein, and fiber, while simultaneously being low in calories. In fact, a half-cup serving of the stuff has 30 percent more protein than regular wheat and just 140 calories. What’s more? A study published in the European Journal of Clinical Nutrition found that eating Kamut reduces cholesterol, blood sugar, and cytokines (which cause inflammation throughout the body). Kamut’s ability to stabilize blood sugar and reduce inflammation make it a great weight loss staple, especially if it is used in place of nutritionally lacking refined grains.
A big reason to incorporate more strawberries into your diet: not only do they taste delicious, but a study from Harvard Medical School found that an increased intake of flavonoid-rich fruits, like strawberries, could help prevent weight gain. Stock up on the seasonal fruit in summer, but don't shy away from grabbing the frozen variety once colder temps hit — fruit is frozen at its nutrient peak, so you'll still nab most of the same health benefits.

From a psychological and cultural perspective, a healthier diet may be difficult to achieve for people with poor eating habits.[48] This may be due to tastes acquired in childhood and preferences for sugary, salty and/or fatty foods.[49] In the UK, the chief medical officer of the government recommended in December 2018 that sugar and salt be taxed to discourage consumption.[50]
Speaking of flavonoids, the waist-whittling compounds also exist in higher concentrations in red fruits such as watermelon, Pink Lady apples, and plums, meaning they also have the power to induce weight loss. In fact, a 2016 study in the journal BMJ found that people who eat a diet rich in flavonoid-heavy food tend to gain less weight, which could be promising seeing as many people tend to put on pounds as they age. In addition, anthocyanin, a specific flavonoid compound that gives red fruits their color, has been shown to reduce fat-storage genes.
Sure, nuts aren’t known for being low in calories, but they have an array of other properties—namely a high protein and fiber content—that makes them ideal for weight loss. A study published in the Journal of the American Heart Association, Circulation, found that consuming 1.5 ounces of almonds daily (as opposed to a carb-dense muffin) along with a heart-healthy diet, helped to improve cholesterol and lipid profiles among the research participants. The study also found that eating almonds reduces belly fat, too.
×