Comparison of the effects of four commercially available weight-loss programmes on lipid-based cardiovascular risk factors

Abstract

Objective: To investigate the relative efficacy of four popular weight-loss programmes on plasma lipids and lipoproteins as measures of CVD risk. Design: A multi-centred, randomised, controlled trial of four diets -Dr Atkins' New Diet Revolution, The Slim-Fast Plan, Weight Watchers Pure Points programme and Rosemary Conley's 'Eat yourself Slim' Diet and Fitness Plan -against a control diet, in parallel for 6 months. Setting and subjects: The trial was conducted at five universities across the UK (Surrey, Nottingham, Ulster (Coleraine), Bristol and Edinburgh (Queen Margaret University College)) and involved the participation of 300 overweight and obese males and females aged 21-60 years in a community setting. Results: Significant weight loss was achieved by all dieting groups (5-9 kg at 6 months) but no significant difference was observed between diets at 6 months. The Weight Watchers and Rosemary Conley (low-fat) diets were followed by significant reductions in plasma LDL cholesterol (both 212?2 % after 6 months, P , 0?01), whereas the Atkins (low-carbohydrate) and Weight Watchers diets were followed by marked reductions in plasma TAG (-38?2 % and -22?6 % at 6 months respectively, P , 0?01). These latter two diets were associated with an increase in LDL particle size, a change that has been linked to reduced CVD risk. Conclusions: Overall, these results demonstrate the favourable effects of weight loss on lipid-mediated CVD risk factors that can be achieved through commercially available weight-loss programmes. No detrimental effects on lipid-based CVD risk factors were observed in participants consuming a low-carbohydrate diet. KeywordsLipids Lipoprotein sub-fractions Weight-loss programmes Cardiovascular diseaseThe prevalence of obesity in the UK is increasing, with 41 % of adult men and 33 % of women being overweight and an additional 25 % and 20 % respectively being obese (1) . As the health, economic and social costs of obesity have become increasingly apparent, the number and variety of weight-loss programmes has multiplied. Numerous dieting programmes are currently available that focus on different strategies for reducing energy intake, by restricting specific macronutrients (fat or carbohydrate), controlling portion size or replacing meals with substitutes.Obesity is one of the major modifiable risk factors for CVD. Weight loss per se results in favourable changes in blood lipid profiles, decreasing circulating LDL cholesterol (LDL-C) and TAG levels and increasing HDL cholesterol (HDL-C) if weight loss is maintained (2) .However, restriction of specific macronutrients can produce differential effects on lipid profiles. High-carbohydrate, low-fat diets, while decreasing LDL-C, have a tendency to increase plasma TAG concentrations and decrease HDL-C (3) , whereas low-carbohydrate diets, though effective in lowering plasma TAG concentrations, can be inherently high in saturated fat and cholesterol and show variable effects on LDL-C (4)(5)(6)(7)(8) . Obesity is frequently associated with raised plas...

Effects of low-carbohydrate dietsv. low-fat diets on body weight and cardiovascular risk factors: a meta-analysis of randomised controlled trials

“…Furthermore, subjects on the LF diet were imposed a energy restriction, whereas subjects on the LC diet were mostly on an ad libitum diet, except in two studies where the LF and LC groups were isoenergetic (14,39) . However, in some of the studies, subjects on ad libitum LC diets also demonstrated a decrease in their energy intake, similar to subjects on the LF diet, although this was not required or encouraged at the outset (11,27,29,30,38) . Most studies offered group or individual sessions of dietary and supportive counselling, whereas one study had a self-help format with little contact with professionals (28) .…”

“…This supports the view that weight reduction itself leads to a shift towards pattern A. The dietary effects on LDL-cholesterol particle size warrant further investigations, especially with regard to establishing whether some individuals can benefit from one diet over another.Several studies showed that macronutrient composition did not seem to be the determining factor in the effectiveness of losing weight when energy intake is also decreased (14,29,36,38) . LC dieters reduced the energy intake upto 30 %, which was a significant reduction compared with baseline intake and comparable with subjects on the LF diet (11,(27)(28)(29)30,36,38) .…”

Macronutrients and type 1 diabetes (revision number 6)

“…Twenty seven randomised controlled trials that presented evidence on diets differing in the proportion of carbohydrate to protein and fat on fasting triacylglycerol were included in the meta-analysis (Clevidence et al, 1992;Golay et al, 1996;Brehm et al, 2003;Johnston et al, 2004;Pereira et al, 2004;Meckling et al, 2004;Brehm et al, 2005;Dansinger et al, 2005;Ebbeling et al, 2005;Layman et al, 2005;O'Brien et al, 2005;Seshadri et al, 2005;Krauss et al, 2006;McMillan-Price et al, 2006;Noakes et al, 2006;Keogh et al, 2007;Gardner et al, 2007;Mahon et al, 2007;Meckling & Sherfey, 2007;Maki et al, 2007b;Keogh et al, 2008;Phillips et al, 2008;Stoernell et al, 2008;Morgan et al, 2009;Sacks et al, 2009;de Luis et al, 2009b). Seven trials were subsequently identified in the update search (Al-Sarraj et al, 2010;Klemsdal et al, 2010;Lim et al, 2010;Hernandez et al, 2010;Wycherley et al, 2010;Krebs et al, 2010;Wood et al, 2012) (Cardio-metabolic review, the hyperlipidaemias and blood lipids chapter p 162-164; Update search table 75).…”

“…Four randomised controlled trials were identified that presented evidence on diets differing in the proportion of carbohydrate to fat or protein in relation to blood glucose response two hours after an oral glucose tolerance test (Swinburn et al, 2001;Lasker et al, 2008;Due et al, 2008a). No further trials were identified in the update search (Cardio-metabolic review, diabetes chapter p185) (Racette et al, 1995;Golay et al, 1996;Golay et al, 2000;Swinburn et al, 2001;Helge, 2002;Colette et al, 2003;Landry et al, 2003;Lovejoy et al, 2003;Wolever & Mehling, 2003;Clifton et al, 2004;Segal-Isaacson et al, 2004;Dansinger et al, 2005;Lofgren et al, 2005;Raatz et al, 2005;Petersen et al, 2006;Howard et al, 2006b;Ebbeling et al, 2007;Gardner et al, 2007;Maki et al, 2007b;Phillips et al, 2008;Due et al, 2008a;Frisch et al, 2009;Grau et al, 2009;Kirk et al, 2009;Morgan et al, 2009;Sacks et al, 2009). Five trials were subsequently identified in the update search (Goree et al, 2011;Haufe et al, 2011;Shikany et al, 2011;Tierney et al, 2011;Brooking et al, 2012 Nearly all trials employ energy restricted weight loss diets that vary both carbohydrate (between 5% and 65% energy) and fat (between 18% and 40% energy) between groups.…”

“…Seventeen randomised controlled trials that presented evidence on diets differing in the proportion of carbohydrate to fat and protein in relation to energy intake were included in a meta-analysis (Borkman et al, 1991;Volek et al, 2004;Meckling et al, 2004;Brehm et al, 2005;Dansinger et al, 2005;Layman et al, 2005;Nickols-Richardson et al, 2005;Seshadri et al, 2005;McMillan-Price et al, 2006;Dyson et al, 2007;Rankin & Turpyn, 2007;Keogh et al, 2008;Lasker et al, 2008;Stoernell et al, 2008;Layman et al, 2009;Morgan et al, 2009). Only two trials provide an energy restriction goal (Borkman et al, 1991;Volek et al, 2004) (Cardio-metabolic review, energy intake and eating motivation chapter p 68).…”