For many decades now, health authorities have recommended a low-fat diet. This recommendation has been widely accepted in the mainstream medical community. Although recent studies have raised some questions about the validity of these guidelines, most health authorities have not changed their position.
The issue is still controversial and the guidelines remain largely unchanged, even though their scientific foundation has weakened. So are low-fat diets truly effective at preventing heart disease or promoting weight loss? This article sums up the evidence.
What Is a Low-Fat Diet?
The standard low-fat diet recommended by health authorities contains less than 30% of daily calories from fat. Very low-fat diets generally provide 10–15% (or less) of total calories from fat. Additionally, many health guidelines recommend that the daily calorie contribution of saturated fat should not exceed 7–10%. Most studies investigating low-fat diets seem to follow these definitions.
Are Low-Fat Diets Good For Weight Loss?
Low-fat diets are often recommended for people who need to lose weight. The main reason behind this recommendation is that fat provides a greater number of calories per gram compared to the other major nutrients, protein and carbs. Fat provides roughly 9 calories per gram, whereas protein and carbs provide only 4 calories per gram.
Studies show that people who reduce their calorie intake by eating less fat lose weight. Although the weight loss is small, on average, it is considered relevant for health. But how effective is a low-fat diet compared to a low-carb diet?
Low-Fat vs Low-Carb
Low-carb diets are usually high in both protein and fat. When food intake is closely monitored and controlled, low-fat diets seem equally as effective for weight loss as low-carb diets. At least, these were the results of a small study in 19 obese adults who spent two weeks in a metabolic ward, which is a highly controlled lab environment. However, the study period was short and the environment didn’t reflect a real-life situation.
Studies in free-living people generally agree that low-fat diets are not as effective as low-carb diets. The reason for this inconsistency is unclear, but the most likely explanation is that low-carb diets are usually associated with greater dietary quality. They tend to focus on whole foods, such as vegetables, eggs, meat and fish. They also encourage skipping most junk foods, which are usually high in refined carbs or added sugar. Additionally, low-carb diets based on whole foods tend to be higher in both fiber and protein than low-fat diets.
A successful low-carb diet may promote weight loss in the following ways:
Lowers calorie intake: A high protein intake decreases calorie intake by suppressing appetite and increasing the number of calories burned.
Increases fullness: A high intake of certain types of fiber may reduce calorie intake by increasing fullness (9Trusted Source).
Fights cravings: Low-carb diets may suppress carb and sugar cravings (10Trusted Source).
Simply put, low-carb diets work because they promote a healthier diet. In contrast, going on a low-fat diet without emphasizing food quality may lead to an increased intake of junk foods high in added sugar and refined carbs.
Low-fat and low-carb diets are equally effective for weight loss in highly controlled situations. However, in free-living obese people, low-fat diets tend to be less effective than low-carb diets.
The Low-Fat Guidelines and the Obesity Epidemic
The low-fat guidelines were first published in 1977. Since then, many of the major health organizations have not changed their position. One thing is clear. Eating less fat is not always the best way to lose weight. Low-carb diets tend to be more effective for most people. Rather than worrying about your total fat intake, focus on improving the quality of your diet. Eating more whole foods and healthy fats is a good way to start.
