By Carrie Dennett, MPH, RDNEnvironmental Nutrition
There’s a certain logic to the idea that eating high-fat foods—even nutritious foods such as avocados, nuts, and olive oil—can lead to weight gain. After all, one gram of fat contains nine calories, while one gram of protein or carbohydrate contains only four calories. But just as science has debunked the idea that weight loss or weight gain is simply the result of “calories in, calories out,” the idea that eating fat automatically leads to eating excess calories, or that dietary fat is directly converted to body fat has been shown to be not entirely correct.
Low-fat Origins
The low-fat diet trend of the 1970s to 1990s was largely based on concerns about saturated fats and health. The weight loss industry—including many diet book authors—jumped on that bandwagon, promoting the idea that if you eat as little calorie-dense fat as possible, you can eat a larger volume of food and still lose weight. But instead of replacing saturated fat with healthy poly- and monounsaturated fats or more vegetables, fruits, and whole grains, many people started eating more ultraprocessed fat free cookies, crackers, and ice cream high in added sugar and refined carbohydrates.
