Why Eating More Fat Can Help You Lose Weight: A Doctor Explains

If you fear fat, you're not alone. I once subscribed to that outdated myth, too. After all, eating fat makes you fat, right?

From a caloric perspective, that seems to make sense. Dietary fat contains nine calories per gram, versus the four calories per gram for carbs and protein. So if you eat less fat, you’ll eat fewer calories and you’ll lose weight, right?

Unfortunately, that theory doesn’t work. The idea that all calories have an equal impact on your weight and metabolism remains one of the most persistent nutrition myths — and it's one that keeps us overweight and sick.

Studies show that healthy fats — not militant calorie counting or low-fat diets — can help you get lean. 

Sure, all calories are the same in a laboratory when you burn them in a vacuum. Your body isn’t a laboratory, though; it’s an intricate, interconnected organism that simultaneously juggles thousands of duties.

Food isn't just calories or a source of energy; it's information that affects every biological function in your body. Food can literally "turn on" health genes or disease genes. Food influences your hormones, your brain chemistry, your immune system, and even your gut flora.

That idea becomes very empowering: You can change your health starting with your very next meal!

Studies show that healthy fats, not militant calorie counting or low-fat diets, can help you get lean. In human experiments, those who ate high-fat diets had a much faster metabolism. Low-fat, high-carb diets spiked insulin, subsequently slowing metabolism and storing as belly fat. The higher-fat diet group had a faster metabolism, even while eating the same amount of calories.

Other research, conducted by Dr. David Ludwig and his Harvard colleagues, compared high-fat, low-carb diets with high-carb, low-fat diets in a controlled feeding study (where researchers provide all the food). Again, the high-fat group did better.

Those researchers subsequently did something called a crossover trial, in which you assign the same study subjects to different diets. For half the study, they ate one way. For the other half, they ate the opposite diet. So half the group ate high-fat, low-carb and half ate low-fat, high-carb; then they flipped those diets for the second part of the study.

This type of study allows researchers to study the effects on metabolism for different diets on the same person, creating a more accurate, comprehensive picture about the most effective eating plan. While their ratios of carbs, proteins, and fats differed, both groups ate the exact same number of calories.

What happened was shocking. The high-fat group ended up burning 300 more calories a day than the low-fat group. The high-fat group also had the most improvements in cholesterol, including lower triglycerides, lower LDL, and lower levels of PIA-1, which shows less likelihood of having blood clots or inflammation. They also showed bigger improvements with insulin resistance or pre-diabetes.

The take-home message here is that most of your fat-cell biology becomes controlled by the quality and type of food you eat. That explains why we should eat a whole-foods diet that’s lower in refined carbohydrates, low-glycemic, and high in fiber and quality fat — including avocados, coconut oil, olive oil, nuts and seeds, and eggs.

Has your perception of dietary fat changed over time? Share your thoughts on my Facebook page. And to learn more myths about dietary fat and find out how to eat quality fats for weight loss and overall health, check out my new book, Eat Fat, Get Thin.

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