Balance Carbs and Fat for Optimal Health

Many popular diets lessen the total amount of a macronutrient, to decrease the total number of kilocalories, leading to weight loss. Fat is the nutrient that is usually cut. This is a flawed approach as carbohydrates, proteins and fats perform different functions and are needed in different amounts. Fat is used by the body as long term energy reserve during starvation sites, as protection for the organs, as insulation during cold temperatures, as components of cell membranes, and as the nutrient from which intracellular messengers are derived from (Gleeson, 2005). If fat is not obtained in the proper amount, either too little or too much, health and performance problems occur.

A low fat diet’s health risks are due to carbohydrates making up a greater percentage of the diet. Dehghan et al. (2017) collected dietary information from 135,335 people, aged 35-70, using food questionnaires, from 18 countries, over a ten-year period. The researchers gathered information regarding all-cause mortality and cardiovascular events, and recorded 5796 deaths and 4784 major cardiovascular disease events. The study showed that diets with >60% carbohydrate (which is typically low in fat) is associated with greater all-cause mortality.

Higher fat diets may also lead to health problems. Many high fat diet studies are conducted on rats ,due to their genetic similarities, it being easier to control their food intake, and ethical reasons. In one study female rats fed a high fat diet (>60%), over an eight-week period, had increased fasting glucose levels, decreased insulin sensitivity, and higher systolic blood pressure than rats fed a low-fat diet (10%) (Roza, Possignolo, Palanch, & Gontijo, 2016). Another study found that rats exposed to a high fat diet increased leptin and Wnt expression, which is associated with tumorigenesis and cancer risk (Penrose et al., 2017). Based on the evidence it seems like neither a very low-fat diet or very high fat diet would be best for the average person.

Based on consuming too little fat leading to an increased risk of death, and a higher fat diet may lead to hypertension and cancer. It would seem for the nonathletic population a diet moderate in fat would be ideal. Based on the work by Denghan et al. (2017) it would seem prudent to lessen the amounts of recommended carbohydrates from 60% of one’s diet to 50-55%. Carbohydrates are the preferred fuel of the body during short term activity and significant cuts (<50% of diet) may hinder performance. Replacing the calories lost through cutting carbohydrates with fats does not increase risk of coronary heart disease, and limiting fats to extreme levels has shown little health benefits. Denghan et al. found that people who consumed around 30-35% of their calories from fat did not have high indicators of cardiovascular disease and recommend fat intake recommendations be revised.

Interestingly, the authors also found that the participants who had relatively high saturated fat intake had a decreased risk of cardiovascular disease. This goes against the current recommendations which say to limit saturated fat intake, but is consistent with the saturated fat intake of ancient hunter-gatherers (Eaton, 2006). Without excessive amounts of saturated fats intake, saturated fat intake can be increased with a subsequent decrease in processed sugars, will not lead to adverse health problems.

It would be smart for the average person to decrease carbohydrate intake and increase fat intake to help prevent chronic disease.

References

Dehghan, M., Mente, A., Zhang, X., Swaminathan, S., Li, W., Mohan, V., . . . Mapanga, R. (2017). Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): A prospective cohort study. The Lancet, 1-13.

Eaton, S. B. (2006). The ancestral human diet: What was it and should it be a paradigm for contemporary nutrition? Proceedings of the Nutrition Society, 65(01), 1-6.

Gleeson, M. (2005). Basic metabolism I: Fat. Surgery (Oxford), 23(3), 83-88.

Penrose, H. M., Heller, S., Cable, C., Nakhoul, H., Baddoo, M., Flemington, E., . . . Savkovic, S. D. (2017). High-fat diet induced leptin and Wnt expression: RNA-sequencing and pathway analysis of mouse colonic tissue and tumors. Carcinogenesis, 38(3), 302-311.

Roza, N. A., Possignolo, L. F., Palanch, A. C., & Gontijo, J. A. (2016). Effect of long-term high-fat diet intake on peripheral insulin sensibility, blood pressure, and renal function in female rats. Food & Nutrition Research, 60(1), 28536-28546.