• Lowering dietary carbohydrates to manage obesity and related disease: A systematic review and theoretical framework

      Fallows, Stephen; Verma, Radhika (University of Chester, 2012-09)
      This study aimed to evaluate the lowering of carbohydrates from conventionally recommended levels of ->55% of energy intake as a valid and safe treatment option for managing obesity and related disease. The study was a qualitative systematic review of fourteen randomized controlled studies, each with at least one study arm that lowered intake of carbohydrates to either ketogenic levels (->50g/) (Atkins type diet) or non-ketogenic levels including Zone type diets (>50g/d to 40-45% of energy intake). Low carbohydrate diets have generally implied increased protein intake to around 30% of energy intake. Outcomes evaluated included weight and fat loss; dyslipidemia; blood sugar control; hypertension; nutritional adequacy; hunger and satiety; adherence and safety. A synthesis of process, results and implications was used towards generating a theoretical weight maangement framework. In the short to medium term of up to six months both the ketogenic and non-ketogenic lowering of carbohydrates within the context of a calorie reduction of 300-750 kcal/day generated clinically meaningful weight loss results of 5-10% Lower-carbohydrates diet plans generated similar or better results for most of the main outcomes examined as comparted with conventional higher-carbohydrate/low-fat diet alternatives. Longer-term studies were few in number but weight loss results were in the range of 2-6% with no significant diet difference noted. Potential impact of ketogenic diets on dyslipidemia, renal and bone health needs further evaluation. When lowering carbohydrates or calories, nutritional adequacy may require maangement with the use of supplementation. Lowering carbohydrates may provide an important and useful strategy to achieve a regular daily caloriee deficit, generate clinically meaningful weight loss and improve related metabolic health markers. Recommended weight management protocols may be individualised based on a theoretical model that considers individual health risks and genetics, dietary preferences, carbohydrate sensitivity and is geared towards improved adherence.