Diet vs. exercise for improving clinical outcomes in people with type 2 diabetes Original paper

In this randomized controlled trial in participants with type 2 diabetes, the results suggested that consuming a 5:2 diet was better than an exercise intervention for improving HbA1c.

The effects of a 5:2 diet or an exercise intervention on glycemic control and cardiometabolic health in participants with type 2 diabetes (T2D).

The primary outcome was HbA1c. The secondary outcomes were other measures of glycemic control (i.e., 2-hour postprandial (postmeal) glucose, fasting glucose, and HOMA-IR), the incidence of T2D remission (defined as an HbA1c of <6.5% without taking antidiabetic medications), anthropometrics (body measurements) and body composition, liver fat, blood pressure, and blood lipids.

326 Chinese adults (average age of 53; 64% men, 36% women) with T2D and overweight or obesity.

The participants had been diagnosed with T2D within the past 2 years and had an HbA1c of 7.0%–8.9%.

In this 12-week randomized controlled trial, the participants were assigned to consume a 5:2 diet, to an exercise intervention or to routine lifestyle education (the control). In the diet group, the participants consumed about 790 kcal per day from liquid formula supplements twice per week (usually on consecutive days). There was no restriction on energy intake on the other 5 days, and the participants had regular contact with a registered dietitian.

The exercise intervention consisted of 2 supervised exercise sessions per week, which included a single bout of 4 minutes of high-intensity interval training performed on a cycle ergometer followed by 4 machine-based resistance exercises performed for 2 sets of 8–12 repetitions. In the control group, the participants received lifestyle advice based on the Guidelines for the Prevention and Treatment of Type 2 Diabetes in China.

Compared to the control group, HbA1c decreased in the diet group (−0.34%), whereas there was no difference between the exercise group and control group. Remission was achieved by 19.4% of participants in the diet group, 12% in the exercise group, and 10.5% in the control group. The likelihood of achieving remission was significantly higher in the diet group than the control group, whereas there was no difference between the exercise group and the control group. Other measures of glycemic control did not differ between groups.

Compared to the control group, weight decreased in the diet group (−1.94 kg), and so did BMI and waist circumference. There were no differences between the control group and the exercise group. Liver fat and body fat decreased in both the diet group and the exercise group compared to the control group. The change in lean body mass did not differ between the diet group and the control group, but lean body mass decreased in the control group compared to the exercise group.

Compared to the control group, diastolic blood pressure decreased in both the diet group and the exercise group by about 2.50 mm Hg. HDL-C trivially increased in the diet group compared to the control group.

The researchers did not adjust for multiple comparisons, which increases the risk of false-positive results. Thus, the secondary outcomes should be interpreted with caution.