Why low-fat diets could increase your risk of cardiovascular diseases, diabetes, and obesity

Rachele Bernardini

Typical nutritional information on food labels categorise food based on their single nutrient content like fats, sugars, and proteins. However, food is consumed whole, and its health benefits derive from a combination of proteins, carbohydrates, fats, micronutrients, phytochemicals, and its preparation techniques. Focusing on isolated nutrients can lead to wrong dietary choices, like low-fat diets, that could have a detrimental effect on your long-term health.

Current official dietary guidelines recommend that less than 35% of your daily energy intake derives from fats (with saturated fats less than 11%)(1) and some low-fat diets promote as little as 20%. Originally the motivation to promote restriction of total fat was to reduce saturated fat and cholesterol as it was believed that these could increase the risk of cardiovascular diseases and obesity.

However, an extensive scientific review(2) has now demonstrated that the overall saturated fat intakes have little relation to health, bringing into doubt current conventions. Studies (3,4) have shown for example, that regular consumption of cheese and yogurt is associated with a lower risk of cardiovascular diseases, diabetes, and obesity. This health benefit is not observed in milk, suggesting that the presence of probiotics and fermentation influences the health benefits of different types of dairies. Limiting the consumption of cheese and yogurt based only on their saturated fat content could lead to incorrect choices for the prevention of chronic diseases.

In addition, low-fat diets could also discourage the consumption of many healthy high-fats foods, like nuts and vegetable oils, which also have been proved to reduce the risk of cardiovascular diseases, diabetes, and obesity even when consumed in excess of the daily 35% recommended (5,6).

Furthermore, in food products where dietary fats are reduced or removed, the fats are commonly replaced by refined carbohydrates including highly processed grains, potato products, and added sugars which are associated with development of the metabolic syndrome, which increases the risk of cardiovascular mortality (7).

Therefore, it can be seen that specific foods, and not the single nutrients within the food, have a greater influence on health, and promoting low-fat food could paradoxically prevent the achievement of optimal health.

So, anyone considering a single nutrient reducing diet, like a low-fat diet should instead replace it with an evidence-based food-based diet, high in vegetables, fruits, whole grains, seafood, nuts, and legumes, and possibly also cheese and yogurt, to prevent the development of cardiometabolic diseases in the long term. And perhaps in the future, we should aim to replace the current traffic light food labels, wrongly based on a single-nutrient model, with a more comprehensive food-based health indicator?

References:

1. SACN Scientific Advisory Committee on Nutrition- Dietary Reference values for energy- 2011 https://www.gov.uk/government/publications/sacn-dietary-reference-values-for-energy. Accessed on 16/02/22.

2. Mozaffarian D. Dietary and Policy Priorities for Cardiovascular Disease, Diabetes, and Obesity: A Comprehensive Review. Circulation. 2016;133(2):187-225.

3. Walther B, Karl JP, Booth SL, Boyaval P. Menaquinones, Bacteria, and the Food Supply: The Relevance of Dairy and Fermented Food Products to Vitamin K Requirements. Advances in Nutrition. 2013; 4(4): 463–473.

4. Qin LQ, Xu JY, Han SF, Zhang ZL, Zhao YY, Szeto IM. Dairy consumption and risk of cardiovascular disease: an updated meta-analysis of prospective cohort studies. Asia Pac J Clin Nutr. 2015; 24:90–100.

5. Gadgil MD, Appel LJ, Yeung E, Anderson CA, Sacks FM, Miller ER. The effects of carbohydrate, unsaturated fat, and protein intake on measures of insulin sensitivity: results from the OmniHeart trial. Diabetes Care. 2013; 36:1132–1137.

6. Howard BV, Van Horn L, Hsia J, Manson JE, Stefanick ML, Wassertheil-Smoller S, Kuller LH, et al. Low-fat dietary pattern and risk of cardiovascular disease: the Women’s Health Initiative Randomized Controlled Dietary Modification Trial. JAMA. 2006; 295:655–666.

7. Panagiotakos DB, Pitsavos C, Skoumas Y, Stefanadis C. The Association between Food Patterns and the Metabolic Syndrome Using Principal Components Analysis: The ATTICA Study, Journal of the American Dietetic Association. 2007; 107(6): 979-987.