Instead of bouncing from one diet to the next (yo-yo dieting), make permanent lifestyle changes. Adopt an active lifestyle and healthy eating habits such as:
- Vary the types of foods you eat.
- Prepare foods with the healthiest cooking methods.
- Know and serve yourself the appropriate portion size for your age and weight.
Variety 
No single food can provide all the nutrients the human body needs. Include a variety of foods in your meals so that the nutritional content of one complements the deficiencies of the others.
A dish of boiled potatoes, roasted chicken and a colorful salad provides the carbohydrates, protein, fat, and vitamins and minerals the body needs.
Variety is as important within a food group, as it is in an entire meal. For example, though grains, cereals or starchy vegetables are all good sources of carbohydrates, their individual composition may be completely different in terms of other important nutrients they contain. Potatoes contain more vitamin C than rice, for example. And cassava (yucca) contains more fiber than potatoes.
All fruits and vegetables provide significant amounts of vitamins, but the specific amounts they contain varies considerably from one fruit or vegetable to another.
Healthy food preparation
The way you prepare your food is an important factor in determining the quality of your diet. For example, you can prepare a potato in many ways. There is a big difference between eating a large oven-baked potato with the skin and eating a serving of french fries. In this example the oven-baked potato is very high in fiber and vitamin C, whereas the french fries have lost much of their nutritional value through processing (if not homemade) and are also high in fat from being fried in oil.
The nutritional value of eating a baked potato changes when high-fat condiments such as butter, sour cream, cheese and bacon bits are added.
Many foods taste good just steamed, baked, or broiled. There is little need to add a lot of "extras" if you know how to add flavor through using herbs and spices. Smothering foods with high-fat condiments actually takes away from the food item itself, and hides its unique flavors and textures. Try to minimize the amount of added fat and oil you use in the kitchen.
Moderation in portion sizes
In addition to the variety of food you eat, and how it is prepared, it is also important to make sure that the amount of food you are eating is appropriate for your age and height.
As with anything else, too much of a good thing can be unhealthy.
Let's use the example of olive oil. Olive oil is an excellent source of unsaturated fat, which is recommended for a healthy cardiovascular system. However, if your intake of olive oil is excessive, then instead of being healthy for you, it can contribute to weight gain and its related problems.
