Modern nutritional science tells us fats, especially saturated fats, are bad for us for two reasons. First, fats make you fat, and second, they lead to high cholesterol and heart disease. But these ideas are losing steam (and not nearly fast enough).
Fats provide many more calories than the other main nutrients — nine calories per gram, compared with four for both carbs and protein. While it does seem logical that the more “calorie-dense” foods you eat, the more weight you gain, in the real world this isn’t how it works. Our bodies have mechanisms to regulate our weight, so even if you eat more than you burn, it doesn’t necessarily get stored as fat.
But this weight-regulating mechanism is susceptible to being thrown out of whack by our modern diets. Of course, a big part of weight regulation is hunger, and sugar has long been known to cause cravings, to the point of being considered addictive. It seems sugar affects the appetite centers of the brain, so it takes more and more food to feel satisfied.
This effect has been shown in mice as well as humans. In a study on mice, once they had eaten “junk foods” for a while, there were changes in their brains. They overate, became obese, and even refused “healthy” foods when sugary foods no longer were offered.
The type of food that satisfies our appetites the best? Fats, in their natural state. But we don’t eat nearly as many unprocessed fats as our ancestors. Our diets are full of fats that have been altered, sometimes with the goal of improving a food’s nutritional value. This is especially true of most of the new “vegetable oils” (more on that next week). Hydrogenated fats, fried foods and other processed fats do not help us with our appetites; it seems the brain doesn’t recognize them as food so we don’t feel full when we eat them. We rarely overeat veggies or meat, but give us fried foods and sweet desserts and we literally can’t get enough.
After appetite, the next most important part of weight regulation is hormonal. Some hormones cause our bodies to burn fats (think testosterone or thyroid hormone), while others cause us to store it. The primary fat-storing hormone is insulin, which is released when we eat refined carbs such as sugar and white bread products. This makes it more likely that the sugary foods you eat will be converted to fat, as opposed to the calories from healthy foods.
According to modern medical nutrition, the second problem with dietary fats, especially the saturated fats found primarily in meat and animal products, is that they cause heart disease.
Research linking saturated fats to heart disease is decidedly mixed. Some studies have shown a strong link between saturated fat intake and heart disease, others have shown no connection. A review of 21 previously published studies, with a combined total of almost 350,000 subjects, was published in the American Journal of Clinical Nutrition. Its conclusion was that saturated fats in the diet are not linked to heart disease or stroke.
According to science writer Gary Taubes, the reason we have been getting bad dietary advice is because we rely too much on a certain type of research. Large population-based studies that compare people with a disease to those who don’t have it worked great for acute diseases such as epidemics. It was assumed this type of research also would be useful to learn about chronic diseases and the link between lifestyle and disease. Come to find out, it is not very helpful at all, and this type of study has been the source of a lot of the “first it’s good for you, then it’s not” flip-flops that have characterized modern nutritional science.
Modern science has given us some undeniable benefits, but it also has been the source of a tremendous amount of misinformation. No wonder so many of my patients have “given up” and just eat what tastes good to them. I’ll bet my right arm (and that’s a big bet for a chiropractor) that when all is said and done, “scientific nutrition” will end up making the same recommendations I got while in chiropractic school 30 years ago — the healthiest foods tend to be the least processed.
Dr. Michael Noonan practices chiropractic, acupuncture and other wellness therapies in Old Town.