The Effect of a Low-fat, Plant-based Lifestyle Intervention (CHIP) on Serum HDL Levels and the Implications for Metabolic Syndrome Status

A Cohort Study

Lillian Kent; Darren Morton; Paul Rankin; Ewan Ward; Ross Grant; John Gobble; Hans Diehl


Nutr Metab. 2013;10(58) 

In This Article


The study evaluated the pre- to post-biometric changes of 5,046 individuals (mean age = 57.3±12.9 years; 33.5% men, 66.5% women), who self-selected to participate in a CHIP lifestyle intervention conducted in various locations throughout the United States. Consent for the study was obtained from Avondale College of Higher Education Human Research Ethics Committee (Approval No. 20:10:07).

The CHIP intervention, previously described,[5,6,12] encouraged and supported participants to move towards a low-fat, plant-based diet ad libitum, with emphasis on the whole-food consumption of grains, legumes, fruits and vegetables. Specifically, the program recommended less than 20% of calories be derived from fat. In addition, participants were encouraged to consume 2–2.5 litres of water daily and limit their daily intake of added sugar, sodium and cholesterol to 40 g, 2,000 mg, and 50 mg respectively. Furthermore, the program encouraged participants to engage in 30 minutes of daily moderate-intensity physical activity and practice stress management techniques.

Before participating in the CHIP intervention (baseline) and then again at 30 days (post-intervention), participants' height, weight, and BP were taken. In addition, fasting (12-hour) blood samples were collected by trained phlebotomists and analysed for TC, LDL, HDL, TG and FPG levels.

The five risk factors for MetS, as described by the "harmonized definition"[3] are: central obesity (based on population specific waist circumference), raised BP (systolic ≥130 mmHg and/or diastolic ≥ 85 mmHg), elevated FPG (≥5.5 mmol/L), increased TG (≥1.7 mmol/L), and decreased HDL (<1.03 mmol/L in males and <1.3 mmol/L in females). The study participants were classified as meeting these criteria at baseline and post-intervention, however, as waist circumference was not measured in this study, BMI >30 kg/m2 was used as surrogate for central obesity, as suggested by the International Diabetes Federation.[13] Participants were deemed as having MetS if they met three or more of the defining criteria.[3]

The data were analysed using IBM™ Statistics (version 19) and expressed as mean ± standard deviation. The extent of changes (baseline to post-intervention) in the MetS risk factors were assessed using paired t-tests. McNemar chi square test was used to determine changes from baseline to post-intervention in the number of participants who met the five MetS risk factor criteria, as well as the number who were classified as having the syndrome.