There are thousands of dietary supplements on the market, including 40+ essential nutrients alone and in various combinations, i.e. vitamins, minerals, trace elements and fatty acids. However, a number of other nutrients are "conditionally essential", meaning that the body normally can make these molecules, but some people do not make optimal amounts. Examples are L-carnitine, alpha-lipoic acid, the methyl donor betaine,  chondroitin sulfate, coenzyme Q10, choline, amino acids such as tyrosine or arginine, and "essential" sugars normally formed in the body. 
5. Wrap unhealthy foods in tin foil. Wrap healthy foods in plastic wrap. The old saying, “out of sight, out of mind” turns out to have some truth to it. Eating isn’t just a physical event, but also an emotional one. Your mind often determines what it wants to eat based on what your eyes see. Thus, if you hide unhealthy foods by wrapping them up or tucking them away in less prominent places, then you are less likely to eat them.
Use whole grain flour in baking recipes. For some guilt-free indulgence, use whole grain flour in your baking recipes. Whole grain flour includes the bran and the germ which make it more nutritious than its refined counterpart. Start off by subbing half of the flour in the recipe with spelt flour (or any other whole grain flour of your choice) and see how it works. Here are some handy tips for baking with whole grain flours.
As the science of nutrition continually evolves, researchers recognize that nutrients needed to maintain a healthy lifestyle must be tailored to the individual for maximum effectiveness. Recognizing that people are not all alike and that one size does not fit all when it comes to planning and achieving a healthful diet, the Institute of Medicine's dietary guidelines, titled "Dietary Reference Intakes for Macronutrients," stress the importance of balancing diet with exercise and recommends total calories based on an individual's height, weight and gender for each of four different levels of physical activity.
Recent research shows that differences in the content of the selenium in the soil can cause major differences in the concentration of selenium in meat.  For instance, since the soil in Finland is poor in selenium, the authorities decided in the early 1980s to add selenate to commercial fertilizers. A survey of selenium status among 108 healthy young people showed an increase in the blood selenium level of about 50 percent after four years. 
Dynamic contrast. Dynamic contrast refers to a combination of different sensations in the same food. In the words of Witherly, foods with dynamic contrast have “an edible shell that goes crunch followed by something soft or creamy and full of taste-active compounds. This rule applies to a variety of our favorite food structures — the caramelized top of a creme brulee, a slice of pizza, or an Oreo cookie — the brain finds crunching through something like this very novel and thrilling.”
For instance, foods rich in vitamin E and beta-carotene are healthy and can help reduce cancer risk. However, the U.S. Preventive Services Task Force (USPSTF) and the American Academy of Family Physicians (AAFP) recommend against taking vitamin E or beta-carotene for the prevention of cardiovascular disease. People who smoke or are at risk for lung cancer also should avoid beta-carotene. It can increase their risk of lung cancer.