Type 2 diabetes — a lifelong disease, or can it be reversed through what you eat?

Aim of the study: To perform a meta-analysis to investigate the effects of intermittent fasting (IF), as compared with either a control diet (CON) and/or calorie restriction (CR), on body composition and cardiometabolic health in individuals with prediabetes and type 2 diabetes (T2D).

Results: Overall, 14 studies involving 1101 adults with prediabetes or T2D were included in the meta-analysis. IF decreased body weight (WMD -4.56 kg [95% CI -6.23 to -2.83]; p = 0.001), body mass index (BMI; WMD -1.99 kg.m2 [95% CI -2.74 to -1.23]; p = 0.001), glycated haemoglobin (HbA1c; WMD -0.81% [95% CI -1.24 to -0.38]; p = 0.001), fasting glucose (WMD -0.36 mmol/L [95% CI -0.63 to -0.09]; p = 0.008), total cholesterol (WMD -0.31 mmol/L [95% CI -0.60 to -0.02]; p = 0.03) and triglycerides (WMD -0.14 mmol/L [95% CI -0.27 to -0.01]; p = 0.02), but did not significantly decrease fat mass, insulin, low-densitiy lipoprotein, high-density lipoprotein, or blood pressure as compared with CON. Furthermore, IF decreased body weight (WMD -1.14 kg [95% CI -1.69 to -0.60]; p = 0.001) and BMI (WMD -0.43 kg.m2 [95% CI -0.58 to -0.27]; p = 0.001), but did not significantly affect fat mass, lean body mass, visceral fat, insulin, HbA1c, lipid profiles or blood pressure.

Aim of the study: To test the efficacy of time-restricted eating (TRE) in comparison to dietitian-led individualised dietary guidance to improve HbA1c in people with Type 2 diabetes mellitus.

Results: Forty-three participants (56 ± 8 y, BMI: 33 ± 5 kg/m2, HbA1c: 7.6 ± 0.8%) completed the intervention. HbA1c was reduced (P=0.002; TRE: -0.4% (-5 mmol/mol), DIET: -0.3% (-4 mmol/mol)) with no group or interaction effects; TRE was non-inferior to DIET (-0.11%, 95%CI: -0.50% to 0.28%). Body mass reduced in both groups (TRE: -1.7 kg; DIET: -1.2 kg) via ∼900 kJ/d spontaneous energy reduction (P<0.001). Self-reported adherence was higher in TRE versus DIET (P<0.001). When individualised dietary guidance is not available, effective, and/or suitable, TRE may be an alternative dietary strategy to improve glycaemic control in people with Type 2 diabetes mellitus.

Aim of the study: To compare the safety of intermittent fasting (IF) with that of continuous energy-restricted diets (CERD) in patients with T2DM and metabolic syndrome who were overweight or obese and assess their effects on glycemic control and weight loss.

Results: Of 84 retrieved studies, 5 met our inclusion criteria. Of these, four studies comprising 355 participants were included in the meta-analysis. Based on changes in HbA1c (-0.06, 95% confidence interval [CI] -0.27 to 0.16) and fasting plasma glucose (-0.27, 95% CI -0.76 to 0.22), IF and CERD had similar effects on glycemic control. Moreover, IF had a better effect on weight loss (-1.70, 95% CI -3.28 to -0.11 kg). Patients in both groups experienced similar improvements in fasting insulin and lipid profile as well as similar hypoglycemic events. IF is a safe diet pattern and could be implemented for patients with T2DM or metabolic syndrome. Further studies with a larger sample size are needed to verify the effectiveness and safety of IF in patients with T2DM.

Aim of the study: Time-restricted eating (TRE), which consists of restricting the eating window to typically 4 to 8 hours (while fasting for the remaining hours of the day), has been proposed as a nonpharmacological strategy with cardiometabolic benefits but little is known about its metabolic effect on type 2 diabetes mellitus (T2DM). We evaluated whether TRE can improve pancreatic β-cell function and metabolic status in overweight individuals with early T2DM.

Results: As compared to standard lifestyle, TRE induced a 14% increase in ISSI-2 (+14.0 ± 39.2%; P = .03) accompanied by a 14% reduction of hepatic insulin resistance as evaluated by HOMA-IR (-11.6% [-49.3 to 21.9]; P = .03). Fasting glucose did not differ between interventions, but TRE yielded a statistically significant reduction in HbA1c (-0.32 ± 0.48%; P < .001). These metabolic improvements were coupled with a reduction of body weight of 3.86% (-3.86 ± 3.1%; P < .001) and waist circumference of 3.8 cm (-3.8 ± 7.5 cm; P = .003). TRE improved β-cell function and insulin resistance in overweight patients with early diabetes, accompanied by beneficial effects on adiposity.

Aim of the study: To examine the evidence for intermittent fasting (IF), an alternative to calorie-restricted diets, in treating obesity, an important health concern in Canada with few effective office-based treatment strategies.

Results: Intermittent fasting shows promise for the treatment of obesity. To date, the studies have been small and of short duration. Longer-term research is needed to understand the sustainable role IF can play in weight loss.

Aim of the study: Type 2 diabetes is a known complication of obesity and a financial burden on the US healthcare system. The 2022 American Diabetes Association (ADA) guidelines support reducing overall carbohydrate intake for patients with type 2 diabetes to improve hyperglycemia.

Results: Type 2 diabetes is a known complication of obesity and a financial burden on the US healthcare system. The 2022 American Diabetes Association (ADA) guidelines support reducing overall carbohydrate intake for patients with type 2 diabetes to improve hyperglycemia. The ADA has no recommendations about intermittent fasting for patients with type 2 diabetes. This article describes a patient who successfully and safely used a low-carbohydrate diet and intermittent fasting and was able to discontinue medications for type 2 diabetes.

Aim of the study: To review the current evidence on intermittent fasting (IF) and ketogenic diet (KD) as dietary interventions for the management of metabolic syndrome (MetS) and type 2 diabetes mellitus (T2D), including their mechanisms of action, clinical benefits, and potential when used in combination.

Results: Both IF and KD independently show clinically significant benefits in improving metabolic parameters in MetS and T2D, including reductions in HbA1c, fasting glucose, body weight, and triglycerides. Mechanistically, both approaches enhance insulin sensitivity, promote autophagy, reduce inflammation, and activate energy-regulating pathways (AMPK) while inhibiting mTOR. Emerging evidence suggests that combining IF and KD may offer synergistic metabolic effects, although data on long-term safety, adherence, and patient-specific suitability remain limited. IF and KD represent promising, non-pharmacologic strategies for improving metabolic health in patients with MetS and T2D.

Aim of the study: Type 2 diabetes mellitus (T2DM) is a major global health concern. Medical nutrition therapy has a key role in T2DM management, with dietary interventions being central to improving glycaemic control and overall metabolic health.

Results: Low-energy and very-low-energy diets, characterized by moderate to severe caloric restriction, respectively, have also been associated with improvements in cardiometabolic markers and glycaemic regulation. Ketogenic diets promote nutritional ketosis and have shown benefits on glycaemic control, insulin sensitivity and other metabolic outcomes, often preceding substantial weight loss. Intermittent fasting strategies, such as alternate-day fasting or the 5:2 model, and time-restricted eating, have likewise been linked to enhanced glycaemic control and favourable metabolic and cardiovascular effects, although their long-term efficacy and safety require further investigation. This Review aims to provide an evidence-based synthesis of the main nutritional strategies used in the treatment of T2DM, with a focus on their underlying mechanisms, clinical efficacy and potential for sustainable long-term implementation.

Aim of the study: Diet modification can be beneficial in the treatment of type-2 diabetes; but different dietary management approaches can have different impact on pancreatic islet β-cells. Congenic male mice carrying one Ins2-R (B22)E allele (encoding a proinsulin that is predisposed to misfolding, plus three alleles encoding WT proinsulin) develop diabetes prompted by high fat diet-induced weight gain, with exacerbation of β-cell ER stress.

Results: However, diabetes was selectively reversed in animals fed high fat diet alternating with fasting, accompanied by significantly increased islet insulin content, and increased circulating insulin. Blood glucose and serum insulin levels oscillate in animals fed every other day; our data suggest β-cell rest on the fasting day. Mechanisms associated with recovery included decreased islet phospho-eIF2α, accompanied by increased proinsulin synthesis without a corresponding increase of the ER chaperone BiP. We conclude that one of the key features leading to the phenotype of enhanced β-cell maturity involves enhanced insulin biosynthesis without a concomitant increase in β-cell ER stress.