Abstract
Background: Obesity, and its related co-morbidities, is a growing problem that has resulted in the development of numerous weight loss diets, including Mediterranean, Paleo, and Intermittent fasting diets. Whilst weight loss can contribute greatly to reducing the risks of chronic disease, it is vital for health to ensure optimal dietary intakes are achieved.
Objectives: To compare the nutritional intakes, and determine the prevalence of inadequate intakes among overweight Dunedin participants consuming a Mediterranean, modified-Paleo, or intermittent fasting diet.
Methods: This thesis used the first 112 participants enrolled in the SWIFT weight loss study (from a total of 250 possible participants). Participants were able to choose which particular dietary plan they would like to follow. Participant nutrient intakes including all supplements, foods and beverages were gathered with 3-4 day weighed food diaries. Mean nutrient intakes of each diet intervention group and p-values for the differences between groups were calculated using ANOVA. Prevalence of inadequate nutrient intakes was calculated by comparing usual intakes with nutrient EAR’s. The likelihood of inadequate nutrient intakes was calculated through comparisons of mean nutrient intakes with AI values. The PC-Side method described in this study is used to assess usual dietary intakes, which are then analysed through comparisons with appropriate Dietary Reference Intakes (DRI’s).
Results: The demographics and diet choices of our 112 participants were broadly similar to the larger SWIFT sample (n=250). The majority of our 112 participants (57.1%) chose the IF diet, and 28.6% the Mediterranean diet, whereas only 14.3% followed the MP diet. There were no significant differences in energy intakes between diet groups, despite the energy restriction on the IF diet. Analysis of nutritional adequacy revealed that the IF group had a significantly greater prevalence of inadequate intakes of vitamin B6, folate, calcium, magnesium, selenium, and zinc than the Mediterranean diet, and that both groups had a high prevalence of inadequate calcium and folate intakes. The MP participants consumed significantly more cholesterol, SAFA, and MUFA (% energy) than both the IF and Mediterranean diets, and significantly less calcium, and carbohydrate. All groups consumed above the upper limit for sodium and recommendation of 8- 10% TE for SAFA. All diets were at risk of inadequate calcium, dietary fibre, and folate intakes.
Conclusion: Our research reveals that IF participants have a significantly greater prevalence of suboptimal intakes than those consuming a Mediterranean diet. Since energy intakes did not differ significantly between groups, this difference in intakes is likely a result of food choice rather than the energy reduction associated with following an IF diet. All diets appeared to be at risk of suboptimal folate, dietary fibre, and calcium intakes, and excessive SAFA and sodium intakes. Future larger studies focusing on nutrient density of the Mediterranean, Paleo, and IF diets, that have an even spread of participants in intervention groups are required to confirm these findings.