The low-carbohydrate high-fat (LCHF) diet has recently been subject to attention on account of its reported influences on body composition and physical performance. However, the combined effect of LCHF with high-intensity interval training (HIIT) is unclear. A systematic review and meta-analysis were conducted to explore the effect of the LCHF diet combined with HIIT on human body composition (i.e., body weight (BM), body mass index (BMI), fat mass (FM), body fat percentage (BFP), fat-free mass (FFM)) and maximal oxygen uptake (VO2max). Online libraries (PubMed, Web of Science, EMBASE, Cochrane Library, EBSCO, CNKI, Wan Fang) were used to search initial studies until July 2021, from which 10 out of 2440 studies were included. WMD served as the effect size with a confidence interval value of 95%. The results of meta-analysis showed a significant reduction in BM (WMD = −5.299; 95% CI: −7.223, −3.376, p = 0.000), BMI (WMD = −1.150; 95% CI: −2.225, −0.075, p = 0.036), BFP (WMD = −2.787; 95% CI: −4.738, −0.835, p = 0.005) and a significant increase in VO2max (WMD = 3.311; 95% CI: 1.705, 4.918, p = 0.000), while FM (WMD = −2.221; 95% CI: −4.582, 0.139, p = 0.065) and FFM (WMD = 0.487; 95% CI: −3.512, 4.469, p = 0.814) remained unchanged. In conclusion, the LCHF diet combined with HIIT can reduce weight and fat effectively. This combination is sufficient to prevent muscle mass loss during LCHF, and further enhance VO2max. Further research might be required to clarify the effect of other types of exercise on body composition and physical performance during LCHF.

PurposeThis study was designed to probe the effect of downhill running on microtubule acetylation and autophagic flux in rat skeletal muscle.MethodsSprague–Dawley rats were subjected to an exercise protocol of a 90-min downhill run with a slope of −16° and a speed of 16 m·min−1, and then the soleus was sampled at 0, 12, 24, 48, and 72 h after exercise. Protein expression levels of microtubule-associated protein 1 light chain 3 (LC3), p62/sequestosome 1 (p62), α-tubulin, and acetylated α-tubulin (AcK40 α-tubulin) were detected by Western blotting. Alpha-tubulin was costained with AcK40 α-tubulin or cytoplasmic dynein intermediate chain in a single muscle fiber, and LC3 was costained with lysosomal-associated membrane protein 1 in cryosections. To assess autophagic flux in vivo, colchicine or vehicle was injected intraperitoneally 3 d before the exercise experiment, and the protein levels of LC3 and p62 were measured by Western blotting.ResultsDownhill running induced a significant increase in the protein levels of LC3-II and p62, whereas the level and proportion of AcK40 α-tubulin were markedly decreased. Furthermore, the amount of dynein on α-tubulin was decreased after downhill running, and autophagosomes accumulated in the middle of myofibrils. Importantly, LC3-II flux was decreased after downhill running compared with that in the control group.ConclusionsA bout of downhill running decreases microtubule acetylation, which may impair dynein recruitment and autophagosome transportation, causing blocked autophagic flux.