Ask AI Mark explains why dietary fat doesn't cause weight gain, citing scientific studies on metabolism and insulin. He argues that diet composition matters more than fat intake alone, and advocates for higher fat, lower carb eating for better metabolic health.
Hey everyone, welcome to my weekly house call, your chance to ask me your questions and this week's question comes from a patient of mine who wrote, Dr. Hyman, the plan that you're putting me on includes lots of coconut oil and avocados and eggs and even some butter. I can't shake my fear of fat. I think all this food is going to make me gain weight. Help! Well, this is not an uncommon thought. Even I had a fear of fat growing up, and the idea that all calories are the same is why the fat we eat has been demonized and blamed for weight gain. It's why we believe that eating fat makes you fat. You see, if fat has 9 calories per gram versus 4 calories per gram for carbs and protein, then if you eat less fat, you'll eat less calories and you lose weight. Unfortunately, it just doesn't work out like that for many reasons. Then all calories are the same in terms of the effects on your weight and metabolism is one of the most persistent myths in medicine today. They're all the same in a laboratory when you burn them in a vacuum, but not when you eat them. New public policies require restaurants to list calorie contents of their foods, and for labels to highlight in larger type and in boldface calorie content of the food. But this is the wrong strategy because it's based on the idea that it's only a matter of calories. Food is not just calories, it's information. It's not just a source of energy. It contains all the instructions that affect every biological function in your body. It's the stuff that controls everything. Food affects the expression of your genes and determining which ones get triggered to cause or prevent disease. Turns on health genes or disease genes, weight loss genes or weight gain genes. And it influences your hormones and your brain chemistry and your immune system, even your gut flora and of course your metabolism at every level. And it works fast in real time with every single bite. Kevin Hall who's from the National Institute of Health, who studies mathematical systems in biology, has found that in a metabolic ward where every ounce of food and every movement and every breath and calorie burned are carefully measured, that those who ate more fat compared to an identical amount of carbs burned over 100 more calories a day. Now, over a year, that amounts to about a 10-pound weight loss from doing no more exercise. He also reported in studies on brain imaging and brain function that eating more fat shuts off hunger and craving centers in the brain. See, it seems that it's the brain that matters most in controlling food intake and taste preferences and even your metabolism. And the dietary fat, which remember is higher in calories per gram than carbs or protein, can positively impact the whole calorie burning process. It's a mind bender. Now, I want to touch on what really causes weight gain. Most of us assume that overeating makes us gain weight. Sounds like a reasonable assumption, right? But in a brilliant paper in the Journal of the American Medical Association, Harvard professor Dr. David Ludwig lays out the case for a very different view of obesity and metabolism. He says simply that we have it all wrong. It's not eating more and exercising less that makes you fat. It's being fat that makes you eat more and exercise less. Essentially, your fat cells get hungry. and they drive you to overeat. Here's how this plays out in your biology. The first domino to fall is when the carbs or sugar spike insulin. And you don't even have to be overweight at that point. The insulin then drives all the available fuel in your bloodstream into your fat cells, especially the fat cells around your middle, what we call visceral fat or vat or organ fat, also known as belly fat. This stimulates your brain to make you eat more. So carbs, insulin, fuel goes into your cells, eat more. The second thing is this. When you try to restrict calories and exercise more, your body is hardwired to think it's an alarm situation, a starvation problem. And that makes you tired so you move less and you conserve energy and it makes you hungry so you eat more and you go find food. And it slows your metabolism so you don't die. See, attempts at weight loss that follow this eat less, exercise more formula have not been too successful for for most people who try it. It can work for a little bit, but certainly you'll almost always rebound back. In fact, less than 10% of people who lose weight can keep it off for a year. You can walk around hungry and tired for a bit, but not for long. You can shift your body into a starvation state by not eating enough food. And here's where it gets interesting. You can also do it by eating the wrong foods, too much sugar and refined carbs. You see, when you eat a lot of sugar and carbs, It makes your body think you're starving. This is a bit counterintuitive. How could your body act like it's starving when there's plenty of calories and food around? Well, here's how. When you eat sugar or refined carbs or anything that raises your blood sugar, it causes a spike in the hormone insulin. That's the fat storage hormone. This is what starts the vicious cycle going. Now in human experiments, those who ate high fat diets had a much faster metabolism. The low-fat, high-carb diets forced all the food into the cells because of these insulin spikes, which then slowed their metabolism. The group that ate the higher fat diet had a faster metabolism even on the same amount of calories. And that's a good thing. It means you burn more calories when you're just sitting around on your butt doing nothing, watching TV or sleeping. Now, another human study performed by Dr. David Ludwig and his colleagues from Harvard that compared high fat, low carb diets with high carb, low fat diets in a controlled feeding study. That's where researchers provide all the food, found the same thing. And here's what they did. They did something called a crossover trial. That means you use the same study subjects to study different diets. For half the study, they ate one way, high fat, low carb. And half the study, they ate another way, low fat, high carb. Now, this allows you to study the effects on metabolism for different diets on the same person. It makes for a more accurate study. Now for one part of the study, the participants got a low-fat, high-glycemic diet of 60% carbs, 20% protein, and 20% fat, which is considered low-fat. In the second part of the study, they got a very low-glycemic diet and high-fat diet of 60% fat, 10% carbs, and 30% protein. Now they used exactly the same calories for each diet. and 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, that's lower triglycerides and higher HDL, lower levels of PAI-1, which shows a less likelihood of having blood clots and lower inflammation, and the most improvement in insulin resistance or prediabetes. So the most important thing I can tell you, the final dot in our Connect the Dots story that matters most to complete the picture is that most of the biology of your fat cells is controlled by the quality and the type of the food that we eat. Which is why we should eat a higher fat, lower carb, that's low glycemic diet, high in fiber, a whole foods diet rich in healthy fats like avocados, coconut oil, olive oil, nuts and seeds and eggs, which is the plan in my new book, Eat Fat, Get Thin. And now I want to hear from you. Do you include dietary fats in your diet? How has this affected your health? Comment on my Facebook page and if you like this video, share it with your friends and family on Facebook and be sure to submit your questions to DrHyman.com and maybe next week I'll make a house call to you.
