I’ve lost count of the number of times I’ve said it: Fat doesn’t make you fat. It’s a truth I’ve taken for granted for years, having heard it from the lips of many of the country’s best doctors, but it’s still one of the hardest pieces of wellness advice for people to believe. And it makes sense if you’re looking at things from a caloric perspective. Fat has 9 calories per gram while carbs and protein have 4 calories per gram each. If you eat less fat, you’ll be eating fewer calories—and that must result in weight loss, right?
If calories were the be-all-end-all of weight loss, that would be true. But weight gains and losses happen due to a number of complicated systemic processes in your body, including how what you eat affects your blood sugar and the cascade of hormones that follows. Because of how fat affects your mitochondria and your hormones, it’s now widely considered by the country’s best doctors to be a tool for weight loss rather than a hindrance to it. “In my functional medicine clinic, higher blood sugar and higher insulin levels (leading to insulin resistance) is one of the top causes, if not the most common cause, of weight gain and trouble losing weight,” explains Will Cole, D.C., an mbg Collective member and author of the best-selling Ketotarian. “Our body is not a calorie calculator as much as it is a chemistry lab. The foods we eat dynamically instruct our metabolism and biochemistry as a whole how to function.” Cole says that calories matter, but secondarily to the quality and type of food we eat. “Three hundred grams of sugar doesn’t behave the same way in our body as 300 grams of healthy fats do,” he says. “The messages that our food tells our hormones, brain, and microbiome is the foundation of metabolic health or health problems.”
If you’re with me so far (and I know that, even backed by science, it can be hard to let go of the ideas we grew up with, so entangled are they in our psychology—even my own mother still eyes nuts and oils with suspicion), you might be wondering which fats are the best for weight loss. There is a hierarchy, of course—swinging by your local fast food joint for some greasy fries will still negatively affect your body’s fat accumulation because of precisely the systemic issues referenced above. On the other hand, there are a few fats that are particularly suited for helping your body maintain a healthy, happy weight: