Plain language summary
Carbohydrate-restricted diets are prevalent not only in obese people but also in the general population to maintain appropriate body weight. The aim of the study was to investigate, through continuous glucose monitoring, whether carbohydrate restriction for one day in actual life could affect the subsequent blood glucose levels in healthy subjects. The study enrolled ten healthy volunteers (2 males and 8 females), who had normal haemoglobin A1c, with an age range between 20 years and 65 years. The participants wore a continuous glucose monitoring device and were given isoenergetic test meals for 4 consecutive days. Results show that after extreme restriction of carbohydrate, an influence on the blood glucose variability persisted for at least 24 hours in healthy subjects. The day after the low-carbohydrate/high-fat diet, the glucose fluctuation increased significantly when compared with the fluctuations on days after the ingestion of normal carbohydrate diet. Authors conclude that low carbohydrate/high-fat diets can induce increasing blood glucose fluctuations that last for at least all the following day and have adverse effects in daily life.
Abstract
Carbohydrate-restricted diets are prevalent not only in obese people but also in the general population to maintain appropriate body weight. Here, we report that extreme carbohydrate restriction for one day affects the subsequent blood glucose levels in healthy adults. Ten subjects (median age 30.5 years, BMI 21.1 kg/m2, and HbA1c 5.5%), wearing with a continuous glucose monitoring device, were given isoenergetic test meals for 4 consecutive days. On day 1, day 2 (D2), and day 4 (D4), they consumed normal-carbohydrate (63-66% carbohydrate) diet, while on day 3, they took low-carbohydrate/high-fat (5% carbohydrate) diet. The daily energy intake was 2,200 kcal for males and 1,700 kcal for females. On D2 and D4, we calculated the mean 24-hr blood glucose level (MEAN/24h) and its standard deviation (SD/24h), the area under the curve (AUC) for glucose over 140 mg/dL within 4 hours after each meal (AUC/4h/140), the mean amplitude of the glycemic excursions (MAGE), the incremental AUC of 24-hr blood glucose level above the mean plus one standard deviation (iAUC/MEAN+SD). Indexes for glucose fluctuation on D4 were significantly greater than those on D2 (SD/24h; p = 0.009, MAGE; p = 0.013, AUC/4h/140 after breakfast and dinner; p = 0.006 and 0.005, and iAUC/MEAN+SD; p = 0.007). The value of MEAN/24h and AUC/4h/140 after lunch on D4 were greater than those on D2, but those differences were not statistically significant. In conclusion, consumption of low-carbohydrate/high-fat diet appears to cause higher postprandial blood glucose on subsequent normal-carbohydrate diet particularly after breakfast and dinner in healthy adults.
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