Flight activity and glycogen depletion on a low-carbohydrate diet

Correlated changes in stress resistance and biochemical parameters in response to long-term protein restriction in Drosophila melanogaster

Studies in fruit flies, Drosophila melanogaster, have observed considerable variation in the effect of dietary protein restriction (PR) on various fitness traits. In addition, not only are there inconsistent results relating lifespan to stress resistance, but also the long-term effects of PR are unexplored. We study PR implementation across generations (long term) hypothesizing that it will be beneficial for fitness traits, stress resistance and storage reserves due to nutritional plasticity transferred by parents to offspring in earlier Drosophila studies. By imposing two concentrations of PR diets (50% and 70% of control protein) from the pre-adult and adult (age 1 day) stages of the flies, we assessed the stage-specific and long-term effect of the imposed PR. All long-term PR flies showed increased resistance against the tested stressors (starvation, desiccation, H2O2-induced oxidative stress). In addition, we also found long-term PR-induced increased stress resistance across generations. The PR flies also possessed higher protein and triglyceride (TG) content, reduced glucose and unaffected glycogen levels. We also assayed the effect of returning the PR flies to control (AL) food for a single generation and assessed their biochemical parameters to witness the transient PR effect. It was seen that TG content upon reversal was similar to AL flies except for PRI70 males; however, the glucose levels of PR males increased, while they were consistently lower in females. Taken altogether, our study suggests that long-term PR implementation contributes to increased stress resistance and was found to influence storage reserves in D. melanogaster.

Would creatine supplementation augment exercise performance during a low carbohydrate high fat diet?

Low carbohydrate high fat (LCHF) diets are emerging in popularity. Several athletics have adopted LCHF diets in an attempt to improve exercise performance and body composition by enhancing fat utilization. However, these diets impair maximal and supramaximal exercise performance due to limited glycogen stores as well as increasing ratings of perceived exertion (RPE). All of these factors may impact training volume and compliance, leading to less optimal training adaptations over time. In contrast, LCHF diets is an effective strategy for weight and fat mass loss and is beneficial for a variety of metabolic processes. One potential nutritional strategy to off-set the negative aspects of a LCHF is creatine (Cr). Creatine supplementation has been shown to increase muscle power output and reduce the rate of fatigue; thereby allowing individuals to work at a higher intensity for a greater duration. Furthermore, Cr supplementation may positively enhance body composition (gains in muscle mass and possibly aid in fat mass loss). Despite the popularity of both LCHF and creatine supplementation, there is no data available investigating the effects of Cr supplementation on exercise performance and body composition during LCHF diets in humans. We would hypothesize that Cr supplementation may augment exercise performance (anerobic power and strength) during a LCHF diet compared to a LCHF diet and placebo. In addition, combining Cr with a LCHF diet would further increase body fat loss and improve body composition compared to a LCHF diet and/or low-fat diets (LFDs) placebo. Our hypotheses would be under the assumption that total caloric intake and protein intake are matched. Future research is warranted to examine chronic exercise with LCHF diets with and without creatine and compare performance and body composition changes to high carbohydrate diets.