by Lewis Chang, PhD
Many nutrition studies utilizing a low fat diet for weight and health management have not consistently demonstrated reductions in cardiovascular events or mortality. In contrast, higher fat diets have netted improved body composition, diet adherence, and satisfying food preferences. However, it is still unknown whether there is an optimal diet composition of fat content for health benefits.
A balanced high fat diet (BHFD) is a diet with 50/30/20 ratio of fat/carbohydrate/protein in which the fat component consisted of equal proportions of saturated, monounsaturated, and polyunsaturated fat. Previously, researchers from Vanderbilt University reported in that consumption of a BHFD for 16 weeks resulted in significant improvements in inflammatory burden, blood pressure, and vascular function in 144 premenopausal women with Class I/II obesity (i.e., BMI 30-39.9).1
Because several studies have identified racial differences in response to a dietary intervention, researchers from the Vanderbilt study recently investigated whether European Americans (EA) and African Americans (AA) in their study had differential cardiometabolic responses to the BHFD. Specifically, they looked at adiposity, insulin resistance (HOMA-IR), lipoprotein composition, and overall cardiovascular disease risk.2
After 16 weeks of BHFD, there were significant reductions in weight, BMI, waist circumference, total body fat, visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) in all women.2 Furthermore, several race-specific differences were observed:2
- EA women preferentially lost VAT, whereas AA women preferentially lost SAT
- EA women lost more VAT than AA women by ~5% even after adjusting for initial fat mass and weight loss
- Only EA women had significant reductions in fasting insulin levels and HOMA-IR scores
- HDL-cholesterol (‘good’ cholesterol) increased in AA women but decreased in EA women
- EA women showed greater improvements with regard to components of the apolipoprotein B pathway (such as ApoB, VLDL-particle, LDL-particle, triglycerides, LDL-cholesterol)
- AA women showed greater improvements with regard to components of the apolipoprotein A1 pathway (such as ApoA1, HDL-particle, HDL-cholesterol)
Regardless of these race-specific observations, the overall cardiovascular disease risk in premenopausal women with obesity was improved in both EA and AA women.2 TG-to-HDL ratio was improved by 4.3% in EA women and 13.1% in AA women. ApoB-to-ApoA1 ratio was improved by 6.1% in EA women and 3.2% in AA women. And the ASCVD lifetime risk estimation was improved by 5.5% in both groups.2
These data indicate that a BHFD is a feasible and effective dietary approach for body weight and cardiovascular risk management in premenopausal women with obesity. Further studies are needed to help understand what drives the observed racial differences and whether other populations (e.g., postmenopausal women, individuals with established disease) would respond similarly to the diet.
Why is this Clinically Relevant?
- A BHFD may be an effective dietary approach for weight and cardiovascular disease risk management for premenopausal women with obesity
- There may be differential responses to the diet by race with regard to adipose tissue distribution, lipoprotein profile, and insulin resistance
- Nevertheless, a BHFD is effective in reducing overall cardiovascular disease risk regardless of race/ethnicity
Read the Metabolism Clinical and Experimental abstract
References
1. Silver HJ, Kang H, Keil CD, et al. Consuming a balanced high fat diet for 16 weeks improves body composition, inflammation and vascular function parameters in obese premenopausal women. Metabolism. 2014. 63(4):562-573.
2. Niswender KD, Fazio S. Balanced high fat diet reduces cardiovascular risk in obese women although changes in adipose tissue, lipoproteins, and insulin resistance differ by race. Metabolism. 2018. pii: S0026-0495(18)30026-X. doi: 10.1016/j.metabol.2018.01.020.
