Different dietary approaches for the treatment of obesity and the phenotypic responses to these diets.

Hession, Michelle

Abstract

Currents treatments for obesity have been unsuccessful. It is essential that a patient-centred approach for obesity management is developed and for this to be successful other diet and lifestyle approaches need to be considered. A systematic review comparing low carbohydrate vs. low fat diets for the treatment of obesity was carried out. It found that low carbohydrate/high protein diets are as effective as, if not better, for treating obesity and cardiovascular disease risk factors. A randomised controlled trial investigating dietary approaches for the treatment of obesity and its co morbidities was carried out. Variables including weight and body composition, cardiovascular risk factors, adipokines, liver and kidney function, and health and lifestyle factors were measured. Those with metabolic syndrome were also examined. It was hypothesised that there are alternative ways of treating obese subjects depending on their phenotype. Those with a higher BMI tend to have a higher carbohydrate intake rather that a higher fat intake so may be better suited to a low carbohydrate/high protein diet rather than the conventional low fat/energy reduced diet. Subjects were initially treated with the standard dietary approach for obesity (health eating, HE) and if not successful after 3 months were randomised to either a very low calorie diet (Lighterlife, LL) or a protein sparing modified fast (PSMF). All three groups showed a significant weight loss and reduced risk for CVD at 12 months. Significant improvements were seen for plasminogen-activated receptor-1, adiponectin, leptin and IL-6 on HE and LL, but only adiponectin significantly improved on the PSMF. Neither diet showed any detrimental effects for those with a healthy liver and kidney function. Quality of life and levels of depression improved at 12 months. Of the 54 subjects with metabolic syndrome at baseline, 12 remained on HE and 32 were randomised to LL and PSMF. This indicates that most subjects did not suit a low fat dietary approach. They were successful at losing weight on LL and PSMF and showed improvement in MS risk factors, and adipokine levels at 12 months. In conclusion, the study demonstrates that a low fat diet may not necessarily be the first line of approach to treat obese subjects with a BMI over 35 kg/m2, including those with MS. A very low calorie diet such as LL or a PSMF may be better suited to the subject.

Citation

HESSION, M. 2009. Different dietary approaches for the treatment of obesity and the phenotypic responses to these diets. Robert Gordon University, PhD thesis.

• Thesis Type: Thesis
• Deposit Date: Sep 2, 2009
• Publicly Available Date: Sep 2, 2009
• Keywords: Obesity; Diet; Weight loss; Cardiovascular risk; LighterLife; Protein sparing modified fast; Randomised controlled clinical trial; Adipokines; Metabolic syndrome
• Public URL: http://hdl.handle.net/10059/415
• Contract Date: Sep 2, 2009
• Award Date: Apr 30, 2009