Short‐term effects of a low carbohydrate diet on glycaemic variables and cardiovascular risk markers in patients with type 1 diabetes: A randomized open‐label crossover trial.

"Short‐term effects of a low carbohydrate diet on glycaemic variables and cardiovascular risk markers in patients with type 1 diabetes: A randomized open‐label crossover trial. A Ranjan, S Schmidt, C Damm-Frydenberg et al. Diabetes, Obesity and Metabolism Mar 27 2017. See Ranjan 2017"
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"To assess the effects of a high-carbohydrate (HC) diet vs a low-carbohydrate (LC) diet on glycemic variables and CVD risk markers in patients with T1D. Hypothesis was that a LC diet would result in more favorable glycemic values than an HC diet, without affecting key CVD risk markers. "
1 week on each diet
"Targets Carb: ≤50g/day. A maximum daily deviation of 25g allowed but greater deviations had to be made up the next day. Protein: none Fat: none Intake E: 1876kcal/d Carb: 47g/d, 10.2%E Protein: 30.4%E Fat: 59.4%E"
"High-carb diet Targets Carb: ≥250g/d Protein: none Fat: none Reported intake: E: 2036kcal/d Carb: 225g/d, 50.5%E Protein: 21.2%E Fat: 28.3%E"
"Primary: glycemic control and CVD risk factors Included: mean sensor glucose, coefficient of variation (CV), mean amplitude glycemic excursions (MAGE), continuous overall net glycemic action 60 minutes (CONGA60 min), high blood glucose index (HBGI), and low blood glucose index (LBGI); kidney function, cognitive function; HbA1c, lipids. "
"Mean sensor glucose same between diets. The LC diet resulted in more time in the normal range of 3.9 to 10.0 mmol/L (p=.02), less time ≤3.9 mmol/L (p= .03) and less glucose variability, compared to HC diet. Thus, less time in hypoglycemia. CVD risk markers did not differ between the diets."
"Insulin doses WG: NR BG: Y Baseline→1 wk LC: 31.7u/d→21.6 HC: 31.7u/d→38.8 BG SS p=0.001"
"Time in hypoglycemia/normal glucose range WG: NR BG: Y Normal range at 1 wk LC diet: 83% HC diet: 72% BG SS p=0.004"
"Reported as excellent ""We are confident that participants adhered to the diets, based on the amount of carbohydrate intake registered in the insulin pumps. Furthermore, the difference in plasma ketones and serum free fatty acids between diet weeks supported diet adherence."" "
"Glycemic variability WG: NR BG: Y On 5 of 6 measures of glycemic variability, the LC diet was superior to the HC diet. On the other measure the difference was BG NSS. Cognitive function - 3 tests BG NSS; 1 test SS better for HC diet. Creatinine, eGFR BG NSS"
The study resulted in similar mean glucose levels between diet groups. However, mean glucose levels, which were not different between the two diets, may not be an appropriate measure of glucose variability. Continuous glucose monitoring, used in this study, captured significant differences in glucose excursions between high- and low-carb diets.


AHA - American Heart Association;
ALT - alanine aminotransferase;
AMDR - acceptable macronutrient distribution range;
AST - aspartate aminotransferase;
BG - between study groups;
BHOB - beta-hydroxybutyrate;
DBP - diastolic blood pressure;
E- energy, caloric intake;
eGFR - estimated glomerular filtration rate;
FBG - fasting blood glucose;
GGT - gamma-glutamyl transferase;
HDL-C - high-density lipoprotein cholesterol;
iGFR - isotope glomerurar filtration rate;
LDL-C - low-density lipoprotein cholesterol;
NAFLD - non-alcoholic fatty liver disease;
NR - not reported (or data needed for calculation not available);
N - no;
NA - not applicable;
NS - not specified;
NSS - not statistically significant;
SBP - systolic blood pressure;
SS - statistically significant;
TG - triglyceride;
total C - total cholesterol;
V - varied, mixed;
WG - within a study group;
WMD - weighted mean difference;
Y - yes

Number of People in Studies:

3,296 Enrolled in randomized controlled trials on 25% or less carbohydrates
2,626 Completed randomized controlled trials on 25% or less carbohydrates
79.67% 82% completion of studies

Duration of Trial

<6 Months
6-9 Months
1 -2 years
>2 years

# of Trials


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