There is an accumulating body of evidence that eating a healthy diet can improve your mood, reduce anxiety and depression, improve learning ability in children, and even stave off some types of cancer. Some researchers are suggesting that early dementia may be prevented by certain nutritional interventions as well. Despite this, many people still don’t eat a healthy diet. The reasons for this include convenience, cost, skepticism over dieting’s effectiveness in the first place, or simply not realizing how important it is to take care of their overall health.
Scientists estimate that nutrition impacts at least 75% of all human diseases, but it is not a simple equation. Many types of cancer, heart disease, and dementia have multiple causes and risk factors. Our genes don’t tell us how to eat; we humans are the ones who decide what to eat based on cultures and traditions that vary from place to place and time period to time period. Today in the developed world, more than one-third of our average calories comes from processed foods that are high in fat, sugar, or salt—and low in vitamins, minerals, fiber, and other nutrients—prompting some nutrition experts to claim we now have a nutritional crisis.
The World Health Organization (WHO) claims that a healthy diet could prevent up to 25% of heart disease and cancers, 50% of strokes, 60% of type 2 diabetes, and 30% of depression. But the organization also notes that many people may not be getting enough essential nutrients in their diet because they don’t eat enough fruits and vegetables; or they may not eat a wide variety of colors—reds, oranges, yellows, greens, dark greens—in their daily diet; or they may not eat fish rich in omega-3 fatty acids.
The American Heart Association points out that nutrition can reduce the risk of heart disease and some cancers. Weight loss as well as a healthy diet is another strategy for improving health, but the association goes on to state that many factors can affect weight, including obesity, physical inactivity, a genetic predisposition to gain weight or certain types of cancer, and age.