Are low-fat diets effective with weight loss?

There is a common misconception that eating a high amount of fat will increase fat gain whilst eating less-fatty foods will make you lose fat. However, it is a negative caloric balance (eating fewer calories than you burn) that will make you lose fat, not a low-fat diet. The reason why fat often receives such bad media is that each gram of fat contains 9 kcal, as opposed to carbohydrates and protein which contain 4 kcal per gram. It is also easier to over-consume fat because, despite their high-calorie content, they are less satisfying than the other nutrients, increasing the possibility of feeling hungry sooner. This is because carbohydrates and protein are absorbed more quickly which causes blood glucose to rise, as opposed to fats which are absorbed more slowly and lower blood glucose. Fatty foods also have less bulk, making them less satisfying.

There are also other variables that one should consider. Unlike carbohydrates (which are stored first as glycogen and are stored only as fat when consuming more carbohydrates than the body can store glycogen), fat is immediately stored as adipose tissue (stored fat). Increasing the intake of carbohydrates and protein will also increase their oxidation rate (the body burns more of these nutrients), whilst increasing fat intake does not increase fat oxidation. Therefore, over-eating fat will increase fat stores. Body fat stores represent a relatively abundant fuel source even in the leanest of people.

The study by Nordman and colleagues (2006) does show that following a low-fat diet can help you reduce body weight and blood cholesterol. Eating fat, however, also has many benefits (for more on the benefits of fat read the blog an introduction to fats). When eating fats, choose unsaturated fatty acids, especially monounsaturated fats which include omega-3 and omega 6 fatty acids. Diets high in saturated fats increase LDL cholesterol (the bad cholesterol) in the blood and the risk of heart disease. Even though increasing fat intake does not increase fat oxidation, endurance training does. Therefore, if you are looking to lose fat, focus on reducing the unhealthy fats and increasing endurance training instead of cutting down all the fat. Resistance training also helps maintain muscle growth, increasing metabolism (you burn more fat during rest), and giving you a leaner body.

Thanks for reading, and as always stay fit!

Coach Darren

References

Burke, L. M. (2015). Re-examining high-fat diets for sports performance: did we call the ‘nail in the coffin’too soon?. Sports Medicine, 45(1), 33-49.

Hunter, G. R., Byrne, N. M., Sirikul, B., Fernández, J. R., Zuckerman, P. A., Darnell, B. E., & Gower, B. A. (2008). Resistance training conserves fat‐free mass and resting energy expenditure following weight loss. Obesity, 16(5), 1045-1051.

Lawrence, G. D. (2013). Dietary fats and health: dietary recommendations in the context of scientific evidence. Advances in nutrition, 4(3), 294-302.

Nordmann, A. J., Nordmann, A., Briel, M., Keller, U., Yancy, W. S., Brehm, B. J., & Bucher, H. C. (2006). Effects of low-carbohydrate vs low-fat diets on weight loss and cardiovascular risk factors: a meta-analysis of randomized controlled trials. Archives of internal medicine, 166(3), 285-293

Steinberg, D. (2005). An interpretive history of the cholesterol controversy, part III: mechanistically defining the role of hyperlipidemia. J Lipid Res, 46(10), 2037-2051.