If you missed our post last week, hop back over there to read the first 6 big nutrition lies we've been told. Without further ado, #7.
7. Carbs Should Be Your Biggest Source of Calories The mainstream view is that everyone should eat a low-fat diet, with carbs being around 50-60% of total calories. This sort of diet contains a lot of grains and sugars, with very small amounts of fatty foods like meat and eggs. This type of diet may work well for some people, especially those who are naturally lean. But for those who are obese, have the metabolic syndrome or diabetes, this amount of carbohydrates is downright dangerous. This has actually been studied extensively. A low-fat, high-carb diet has been compared to a low-carb, high-fat diet in multiple randomized controlled trials.The results are consistently in favor of low-carb, high-fat diets (34, 35, 36).
Bottom Line: The low-fat, high-carb diet is a miserable failure and has been proven repeatedly to be vastly inferior to lower-carb, higher-fat diets.
8. High Omega-6 Seed and Vegetable Oils Are Good For You
Polyunsaturated fats are considered healthy because some studies show that they lower your risk of heart disease. But there are many types of polyunsaturated fats and they are not all the same. Most importantly, we have both Omega-3 fatty acids and Omega-6 fatty acids. Omega-3s are anti-inflammatory and lower your risk of many diseases related to inflammation (37). Humans actually need to get Omega-6s and Omega-3s in a certain ratio. If the ratio is too high in favor of Omega-6, it can cause problems (38). By far the biggest sources of Omega-6 in the modern diet are processed seed and vegetable oils like soybean, corn and sunflower oils. Throughout evolution, humans never had access to such an abundance of Omega-6 fats. It is unnatural for the human body. Research that specifically looks at Omega-6 fatty acids instead of polyunsaturated fats in general shows that they actually increase the risk of heart disease (39, 40). Eat your Omega-3s and consider supplementing with cod fish liver oil, but avoid the industrial seed and vegetable oils.
Bottom Line: Humans need to get Omega-6 and Omega-3 fats in a certain ratio. Eating excess Omega-6 from seed oils raises your risk of disease.
9. Low Carb Diets Are Dangerous
I personally believe low-carb diets to be a potential cure for many of the most common health problems in western nations. The low-fat diet peddled all around the world is fairly useless against many of these diseases. It simply does not work. However, low-carb diets (demonized by nutritionists and the media) have repeatedly been shown to lead to much better outcomes. Every randomized controlled trial on low-carb diets shows that they: Reduce body fat more than calorie-restricted low-fat diets, even though the low-carb dieters are allowed to eat as much as they want (41, 42). Lower blood pressure significantly (43, 44). Lower blood sugar and improve symptoms of diabetes much more than low-fat diets (45, 46,