Fleming RM, Fleming MR, Harrington GM, Ayoob KT, Grotto DW, Chaudhuri TK and McKusick A
Background: Obesity is caused by eating behaviours. Adherence to all diets has been extremely poor, thus, comparative data on health effects of different diets over periods of a year or more are limited.
Objective: To treat the root causes of obesity by modifying the eating behaviours and to compare the long-term (one year) cardiovascular health affects using three major types of diets under isocaloric conditions including the impact on surrogate markers and most importantly the quantitative measurement of actual coronary artery disease as quantitatively defined using FMTVDM©?.
Methods: Controlled experiment with one year of dieting and a four-month postdiet follow-up in a private practice setting.
Participants: 120 obese, otherwise healthy, adults who are not being seen for other health conditions.
Interventions: Participant agreement to follow and self-manage diet, physician supportive nondirective diet counseling providing follow-up at six-week intervals on food selection and portion control to achieve 1500-1600 calorie intake of assigned diet type: low-to moderate-fat, lowered-carbohydrate, or vegan.
Outcomes: Adherence, weight loss, changes in 14 cardiovascular lipids and coronary blood flow health risk indices.
Results: One-year body mass changes did not differ by diet (P>0.999). Effect sizes (R, R2) for differences between diets were statistically significant for all indices. Coronary blood flow, R (CI95%)=0.48 to 0.69, improved with low-to-moderate-fat and declined with lowered carbohydrate diets. Inflammatory factor Interleukin-6 (R=0.51 to 0.71) increased with lowered carbohydrate and decreased with low-tomoderate- fat diets.
Conclusions: Appropriate diet and exercise with time intensive diet counseling can be effective in weight reduction and maintenance for most people. Nondirective supportive counseling leads to high diet program participant retention. One year of a lowered-carbohydrate diet significantly increases cardiovascular risks. Longterm adherence to a low-to-moderate-fat diet significantly reduces cardiovascular risk factors. Vegan diets are intermediate but close to low-to-moderate-fat in effects. Lowered-carbohydrate dieters were least inclined to continue dieting after conclusion of the study. Reductions in coronary blood flow can be reversed with appropriate dietary intervention. The major dietary effect on atherosclerotic coronary artery disease is inflammation and not weight loss.
