The Effect of High‐, Moderate‐, and Low‐Fat Diets on Weight Loss and Cardiovascular Disease Risk Factors

Abstract

Over 60% of Americans are overweight and a number of popular diets have been advocated, often without evidence, to alleviate this public health hazard. This study was designed to investigate the effects of several diets on weight loss, serum lipids, and other cardiovascular disease risk factors. One hundred men and women followed one of four dietary programs for 1 year: a moderate-fat (MF) program without calorie restriction (28 patients); a low-fat (LF) diet (phase I) (16) ; a MF, calorie-controlled (phase II) diet (38 patients); and a high-fat (HF) diet (18 subjects) [corrected]. Weight, total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), triglycerides (TG), homocysteine (Ho), and lipoprotein(a) [Lp(a)], were measured every 4th month. The TC/HDL-C ratio was calculated and fibrinogen levels were measured at baseline and after one year. The MF diet resulted in a 2.6% (NS) decrease in weight compared with 18.4% (p=0.045) decrease in patients on phase I, 12.6% (p=0.0085) decrease in patients on phase II, and 13.7% (p=0.025) decrease in those on the HF diet. TC was reduced by 5% (NS) in the MF group, 39.1% (p=0.0005) in the phase I group, and 30.4% (p=0.0001) in the phase II group. HF group had a 4.3% (NS) increase in TC. LDL-C was reduced by 6.1% (NS) on MF, 52.0% (p=0.0001) on phase I, and 38.8% (p=0.0001) on phase II. Patients on HF had a 6.0% (NS) increase in LDL-C. There were nonsignificant reductions in HDL-C in those on MF (-1.5%) and HF (-5.8%). Patients on phase I showed an increase in HDL-C of 9.0% (NS), while those on phase II diet had a 3.6% increase (NS) in HDL-C. TC/HDL-C increased (9.8%) only in patients following the high-fat diets (NS). Patients on MF had a 5.3% (NS) reduction in TC/HDL-C, while those on LF had significant reductions on the phase I ( -45.8%; p=0.0001) diet and phase II diet (-34.7%; p=0.0001). TG levels increased on both the MF (1.0%) and HF (5.5%) diets, although neither was statistically significant. People following the phase I and II diets showed reductions of 37.3% and 36.9%, respectively. Ho levels increased by 9.7% when people followed the MF diet and by 12.4% when they followed the HF diet. Patients following the phase I and phase II diets showed reductions of 13.6% and 14.6%, respectively. Only those following phase II diets showed a tendency toward significant improvement (p=0.061). Lp(a) levels increased by 4.7% following the MF (NS) diet and by 31.0% (NS) on the HF diet. Patients following phase I showed a 7.4% (NS) reduction and a 10.8% reduction (NS) following phase II. Fibrinogen levels increased only in individuals following HF diets (11.9%), while patients following MF (-0.6%), phase I (-11.0%), and phase II (-6.3%) diets showed nonsignificant reductions in fibrinogen. Patients on MF demonstrated nonsignificant reductions in weight, LDL-C, TC, HDL-C, TC/HDL-C ratios, and fibrinogen and nonsignificant increases in TGs, Lp(a), and homocysteine. There was significant weight loss in patients on phase I and I...

Effect of weight loss on inflammatory and endothelial markers and FMD using two low-fat diets

“…Similarly, Volek et al 43 did not observe changes in homocysteine after 4 kg of weight loss on a reduced fat diet, with vitamin/mineral supplements including folic acid. Similarly, Fleming 44 in a study of 100 men and women, found no significant effect of weight loss in homocysteine. In crosssectional studies, folate was found to have a greater effect on endothelial function than homocysteine.…”

High-Density Lipoprotein Cholesterol

“…31 The importance of raising HDL-C in reducing cardiovascular and stroke risk has also been highlighted in recent reviews. 3,32 Raising Serum HDL-C Raising serum HDL-C can decrease cardiovascular risk by 5.5% for each 1 mg/dL increment in baseline HDL-C. 33 There are various pharmacological and nonpharmacological means to increase serum HDL-C. 34 Lifestyle-associated improvement in HDL-C appear to be greatest in persons with the highest baseline HDL-C levels (Ն60 mg/dL). 35 Many of these lifestyle modifications have been shown to reduce overall stroke risk, but it is unclear what effect they will have in patients with low-HDL at the highest risk of cardiovascular disease.…”

A review of low-carbohydrate ketogenic diets

“…If a person is consuming below this threshold, then triglyceride will be broken down from adipose tissue to generate ketones to supply the CNS. Most of the small feasibility studies showed that LCKD compliance in a clinical outpatient setting showed promise for weight loss, so more formal randomized, controlled trials (RCTs) were justified [39][40][41][42][43][44].…”