Adults with type 2 diabetes were randomized to two low-calorie days per week or daily calorie restriction for 12 months.

Average long-term blood sugar dropped about 0.5% with daily restriction and 0.3% with intermittent restriction, while fasting glucose and blood lipids did not differ between groups. Weight loss was similar at about 5.0 kg versus 6.8 kg.

Sixty-three adults with type 2 diabetes were randomized to two very low-calorie days per week or daily restriction for 12 weeks.

Average long-term blood sugar decreased by about 0.7% and body weight fell by about 5.9% in both groups, with no meaningful differences in weight, body composition, or medication changes between diets.

Adults with central obesity were randomized to intermittent or continuous restriction for 4 weeks with a goal of equivalent weight loss.

Weight loss was similar at about 2.6% with daily restriction and 2.9% with intermittent restriction, and the insulin-sensitivity score rose by about 6.6% in both groups. Fasting glucose decreased after daily restriction but not after intermittent restriction, and most other cardiometabolic markers were similar.

In this randomized clinical trial, adults with obesity were assigned to alternate-day fasting or daily calorie restriction for a year.

Blood pressure, fasting glucose, fasting insulin, and the insulin-resistance score did not differ between groups at 6 or 12 months. HDL cholesterol rose by about 6.2 mg/dL at 6 months with alternate-day fasting but the difference disappeared by 12 months, while LDL cholesterol increased by about 11.5 mg/dL at 12 months in the alternate-day fasting group.

Adults with abdominal obesity and at least one metabolic-syndrome component were randomized to intermittent or continuous restriction for 6 months with a 6-month maintenance period.

Weight loss was similar at 8.0 kg with intermittent restriction and 9.0 kg with continuous restriction. Improvements in waist circumference, blood pressure, triglycerides, and HDL cholesterol were comparable between groups, indicating no metabolic advantage for intermittent fasting.

Adults who completed a 12-month diet trial were followed for another year to compare long-term outcomes of continuous restriction versus two intermittent patterns.

At 24 months, weight change was -4.5 kg with continuous restriction versus -2.8 kg with week-on/week-off and -3.5 kg with 5:2, while total cholesterol decreased over time and glucose, HDL, LDL, and triglycerides showed no diet-specific differences.

Adults with type 2 diabetes were followed for 24 months after a randomized trial comparing intermittent and continuous restriction.

Average long-term blood sugar increased by about 0.4% in the continuous group and 0.1% in the intermittent group, a small difference that did not demonstrate a clear advantage for either approach over two years.

The HELENA randomized trial compared a 5:2 intermittent restriction plan with continuous restriction at similar overall calorie deficits over 50 weeks.

Across a broad panel of metabolic biomarkers linked to insulin signaling, inflammation, and energy metabolism, the study found comparable improvements between diets and no meaningful metabolic advantage for intermittent fasting.

Premenopausal women with obesity were randomized to two very low-calorie days per week or daily restriction for 8 weeks.

Weight loss was similar at about 6.7 kg versus 6.2 kg, and reductions in liver, pancreatic, and intramuscular fat were comparable between diets. Measures of insulin resistance improved only immediately after the low-energy days, suggesting no sustained metabolic advantage for intermittent fasting.

Adolescents with obesity were randomized to intermittent or continuous restriction within an intensive behavioral program and followed for 52 weeks.

Insulin-resistance prevalence fell from 76.5% to 57.1% in the intermittent group and from 86.8% to 57.1% in the continuous group at week 16, but by week 52 the improvement persisted only in the continuous-restriction group, indicating no metabolic advantage for intermittent fasting over the full year.