Acute ketone supplementation in the absence of muscle glycogen utilization: Insights from McArdle disease

In a randomized crossover design, 8 patients with McArdle disease and 7 healthy controls completed a submaximal test and a maximal ramp test after placebo or a 30 g ketone monoester dose; patients were also tested after 75 g of carbohydrate. Ketone supplementation induced ketosis in all participants (blood ketones 3.7 plus or minus 0.9 mM). Patients had 65 percent lower peak power output than controls (p < 0.001), and ketones impaired it further by 11.6 percent versus placebo (p = 0.001) with no effect in controls (p = 0.268). In patients, carbohydrate gave 21.5 percent higher peak power output than ketones (p = 0.001) and 12.6 percent higher than placebo (p = 0.057).