Unfortunately, intuitive, yet compelling arguments can be made as to why sun exposure and fat consumption might be unhealthy: the sun's UV rays can cause cancer by introducing errors in DNA transcription; heart disease is strongly associated with fatty deposits in the coronary artieries, fatty acids in the blood, and obesity. It is too easy to imagine that these correlates would likely be related to fat consumption. But does research support these intuitions?
It has been well established that vitamin D and calcium deficiencies are at epidemic proportions in America today. Calcium is known for its role in building strong bones and teeth, but it also plays a critical role in food metabolism. The best source of calcium is milk; however, today people prefer sugar-laden beverages over milk. It has been estimated that 75% of Americans are deficient in calcium. A recent study showed an alarming increase in broken bones in today's children compared to those in the 1970's . Rickets is now reappearing among children , and teenagers are being diagnosed with osteoporosis, something that was unheard of in the last two generations.
It has been estimated that 70% of America's children are currently deficient in vitamin D  (Details) . This is not surprising, given current medical advice. The sunscreen industry lobby has convinced most Americans, including medical experts, that the sun should be aggressively avoided to prevent skin cancer. This, in spite of the fact that the sun is an excellent source of vitamin D, allowing the skin to manufacture it directly from cholesterol. Moreover, vitamin D is protective against all cancers (Details) a characteristic which, in my view, more than compensates for any extra skin cancer risk incurred by sunbathing. Vitamin D deficiency is also associated with an increased risk of high blood pressure and diabetes . In order to get vitamin D from food, it is necessary to eat animal fats; animals manufacture vitamin D, a fat-soluble vitamin, and store it in their fat cells.
The American medical establishment is heavily entrenched in the idea that dietary fat is unhealthy. People are encouraged to adopt low fat diets, which inevitably lead to an increase in their intake of carbs and sugars, as much of the fat removed in foods is replaced with sugars to make them palatable. Many foods are also often highly processed and easily digested, leading to a rapid rise in blood sugar. At the same time, foods containing vitamin D are avoided, due to their universally high fat content.
Vitamin D is crucial to the absorption of calcium from the gut into the blood stream, and both vitamin D and calcium are important catalysts in crucial biological processes. Fats also promote the vuptake of calcium in the gut, whereas dietary fiber, touted as being healthy, impedes it  (Details) . These three nutrients, fats, vitamin D, and calcium, have intricate mutual dependiencies that make it important to consume them together. Americans are deficient in these important nutrients because of their perceived need to pursue a low fat diet and avoid sun exposure.