Low-Calorie Diets on Type 2 Diabetes Remission

The prevalence of type 2 diabetes mellitus (T2DM) has been increasing rapidly in China. China currently has \~130 million diabetes cases, and over 90% are T2DM. T2DM is a leading cause of morbidity and mortality, posing substantial clinical and public health challenges. Reversing T2DM with a significant amount of weight loss via consuming a low-calorie diet is possible, but no studies have been conducted to determine whether low-calorie diets will help achieve significant weight loss and diabetes remission among Chinese patients with T2DM. The investigators design a pilot study to assess the feasibility of a low-calorie diet intervention program on weight loss and diabetes remission in a Chinese population with T2DM.

Consistent evidence has shown that overweight and obesity are the leading cause of T2DM, which exacerbates the development of insulin resistance and disease progression. For overweight and obese patients with T2DM, there is a strong consensus that sustained and moderate weight loss can effectively improve glycemic control and blood pressure as well as reduce the need for glucose-lowering medications and improve quality of life.

Short-term dietary interventions using structured low-calorie diets (800-1,000 kcal/day) have shown to be an effective approach for losing weight and promoting sustained diabetes remission in T2DM patients who are overweight or obese. The United Kingdom DiRECT research team designed a structured, intensive intervention program of 12-20 weeks to achieve substantial weight loss and T2DM remission through energy restriction. Researchers recorded ≥15 kg of weight loss in 24% of the participants who underwent a low-calorie formula diet intervention (total diet replacement with 825-853 kcal/day formula low-energy diet meal replacement products). Among these participants, the diabetes remission rate reached 90%.

This non-randomized dietary intervention study comprises 2 study arms: a formula diet (815-835 kcal/day) and a food-based diet (815-835 kcal/day). Participants will be on either of the two low-calorie diets for 12 weeks to achieve at least 12 kg of weight loss (intensive weight loss phase). Participants may extend the weight loss phase if desired. After 12 weeks, participants in the formula diet group are allowed to consume actual meals gradually, and participants in both groups will increase their energy consumption gradually over the next 12 weeks (weight loss achievement and maintenance phase). Physical activity is recommended during the second phase for maintaining weight loss. This study is designed to assess feasibility of the low-calorie diet intervention, in preparation for a full-scale randomized control study. This pilot study also plans to explore potential mechanisms of the intervention for weight loss and diabetes remission.

Eligibility Criteria:
Inclusion Criteria:

* Physician-diagnosed T2DM
* Most recent HbA1c level: 6.5%-12.0%
* Body mass index: 24-45 kg/m2
* Informed consent signed by participants in this study in accordance with requirements of local regulations and the Ethical Review Committee
* No plan to leave Shanghai in 2 years

Exclusion Criteria:

* Type 1 diabetes
* Current use of insulin and glucagon-like peptide-1 receptor agonists
* Major cardiovascular events (e.g., myocardial infarction, stroke, and heart failure) within the previous 6 months
* Weight loss \>5 kg within the past 6 months
* Diagnosed eating disorders or any dieting behaviors
* Chronic kidney disease stage 3b or higher (estimated glomerular filtration rate \<30 milliliter /min/1.73m2)
* Previously diagnosed psychiatric disorders, e.g., schizophrenia, post-traumatic stress disorder, obsessive-compulsive disorder, uncontrolled depression, uncontrolled epilepsy
* Severe arthritis and gout
* Gallstone disease or known asymptomatic gallstones
* Participation in another clinical research trial
* Being pregnant or have a positive pregnancy test result at screening, or have given birth within the past 90 days, or who are breastfeeding.
* Any known cancers
* Learning difficulties
* Alcoholism
* Pancreatitis