Carbohydrate Backloading: A reviewCarbohydrate Backloadingis a dieting strategy that was popularized by John Keifer. This strategy emphasizeson keeping carbs at an absolute minimum throughout the day and ingestingcarbohydrates after the training session. 34Mechanism of carbohydrate Backloading: It was hypothesized that carbohydrate backloadingtakes advantage of the non-insulin mediated uptake of glucose by the muscletissues post-exercise, because of GLUT4 translocation, as opposed to in themorning, when insulin sensitivity in both muscle and fat tissue is generallyhigher 32.Similar to GLUT (GlucoseTransporter) 1-3, GLUT4 and GLUT12 are a set of glucose transporters which arepresent in muscle and fat tissue. While GLUT 1-3 are exposed to the cell surface,GLUT4 are tucked below the surface within the cellular membranes.
Due to thiswithdrawn nature of GLUT4, this only reacts to the presence of insulin bymoving from the interior of the cell to its surface. Thereby, this insulin-mediated transport ofglucose transports high volumes of glucose in the cells containing these GLUTs(both muscle and fat tissue). 33, 34However, resistancetraining mimics the function of insulin in muscle cells and GLUT4 rises to thesurface shuttling glucose into the muscle tissue. This non-insulin mediateduptake of glucose by the muscle tissues post-exercise is postulated to haveincreases in the skeletal muscle tissue without any significant increases inadipose tissue. 34Research on carbohydrate backloading: The most popular researchto support the theory of CBL is a 6 month study. In this study, Sofer et al.
35authors compared the effects of carbs eaten mostly at dinner (experimentalgroup) vs. eaten throughout the day (control group) in a group of 78Israeli police officers. It wasfound that reductions in weight, body fat and waist circumference were greaterin the evening-carb experimental group vs. the control group.
In addition,glucose control, inflammation, blood lipids and satiety were improved to agreater degree in the evening-carb group.However, thereare a few limitations to the design of the study. The subjects were fed a dailyaverage protein intake of 0.
66-0.76 g/kg, which is much less than whatis consumed by resistance trainees aiming for a better body composition, whichquestions the applicability of the research to this population. Also, theexperimental group lost an average 11.8 percent of their body weight in 6months as compared to the control group who lost an average 10.9 percent, whichisn’t statistically significant (<1%) over 6 months.
Also, the experimentalgroup started at a greater weight to begin with.There are othercontrolled studies 36, 37 which were conducted, but no changes in bodycomposition or weight loss were observed, however they were conducted for veryshort durations (15 days and 18 days).SummaryCarbohydrate backloadingdoesn’t provide any additional benefits in fat loss/ muscle gain when comparedto a normal diet when calories and protein are equated.Though, in light ofthe limited evidence, it does seem that shifting caloric (and carbohydrate)intake to later in the day (around the training session) may provide a slightadditional benefit with respect to body composition, better trainingperformance and markers of health and disease.