Dietary fiber (DF) consumption has been associated with improved glycemic control in epidemiological and long-term interventional studies. However, its acute effects are not yet clear. This systematic review aims to elucidate the postprandial effects of DF in starchy products on glycemia and insulinemia. An electronic search of databases was conducted, and forty-one records met the inclusion criteria and underwent a risk-of-bias assessment. It was shown that soluble DF does not clearly affect glycemia in individuals with normal weight, while resistant starch may be more effective in flattening glycemic responses. Concerning insulinemia, both soluble DF and resistant starch have mixed results, with either favorable or no effects. Data on insoluble DF and glucose metabolism are scarce. The same mixed results for glycemia can be seen in healthy volunteers with overweight/obesity, while resistant starch seems to improve insulinemic responses. Finally, more studies need to examine the acute effects of DF in starchy foods on glucose metabolism and insulin secretion in individuals facing glucose abnormalities. Additionally, more studies are needed to prove whether ingesting high-fiber carbohydrate-containing products per se can result in blunted glycemic and insulinemic responses and which DF type and amount are more effective.

Time-restricted feeding (TRF) and Ramadan fasting (RF) have been recently associated with several health outcomes. However, it is not yet clear if they are superior to existing treatments in terms of glucose metabolism, insulin action, and weight loss. This review aims to summarize the current data on the effects of these regimes on body weight, body composition, and glycemia. An electronic search was conducted in PUBMED and SCOPUS databases up to August 2022. Twenty-four records met the inclusion criteria and underwent a risk-of-bias assessment. The main outcomes were: (a) TRF may result in moderate weight loss in individuals with overweight/obesity; when TRF is combined with caloric restriction, weight loss is >5% of the initial body weight, (b) 14 h of fasting may be as effective as 16 h in terms of weight loss, and (c) TRF may lead to improved insulin sensitivity and glycemic responses/variability throughout the day in individuals with overweight/obesity. Concerning RF, only two studies were available and thus, conclusions were not drawn. TRF may be an effective nutritional approach for weight loss, and the amelioration of glycemic control and insulin sensitivity in individuals with overweight/obesity. However, more long-term, well-designed studies are needed.

Background: The Mediterranean diet (MD) is considered the best dietary approach for patients with metabolic dysfunction‐associated steatotic liver disease (MASLD). Recently, time‐restricted feeding (TRF) has gained attention for its lifestyle compatibility and health benefits.Aims: This study aimed to compare the effects of a hypocaloric MD with a 10‐h TRF protocol to an unrestricted MD in MASLD patients with overweight/obesity and evaluate differences between early and late TRF.Methods: This 12‐week randomised controlled trial in MASLD patients with overweight/obesity consisted of three groups, all following a hypocaloric Mediterranean‐type diet. The control group had no eating time restrictions. The early TRF (eTRF) and late TRF (lTRF) groups had a 10‐h eating window, from 8 AM to 6 PM and from 12 PM to 10 PM, respectively. Various health parameters were measured. Compliance was tracked via food diaries, and an 8‐week follow‐up occurred post‐intervention.Results: Fifty‐nine MASLD individuals (27 males; 52.9 years; body mass index 32.1 kg/m²) completed the trial (control, n = 19; eTRF, n = 20; lTRF, n = 20). All groups showed significant 12‐week reductions in body weight, anthropometry and blood pressure. Glycated haemoglobin A_1c and insulin resistance, as measured by the Matsuda index, homeostatic model assessment for insulin resistance and fasting glucose‐to‐insulin ratio, improved in the eTRF group at 12 weeks.Conclusions: This study corroborates the efficacy of MD in ameliorating cardiometabolic risk factors such as body weight and blood pressure in MASLD patients. The combination with an eTRF protocol may improve glycaemic control (NCT05866744).Trial Registration: The study is registered at clinicaltrials.gov (NCT05866744)

Low vitamin D levels have been associated with several diseases as its receptors are expressed in almost all tissues of the human body. Literature data have shown delayed diabetic foot ulcer (DFU) healing in patients with low vitamin D; however, data on the association between vitamin D levels and DFU in Mediterranean countries are scarce. In this cross-sectional study we examined for differences in serum vitamin D levels between patients with DFU, people with diabetes mellitus (DM) without DFU and healthy individuals in a Southern European country. A total of 96 subjects (33 patients with DFU, 35 patients without DFU and 28 healthy controls) were recruited. Medical and dietary history was obtained and total serum 25-hydroxyvitamin D [25(OH)D] levels were determined. Serum vitamin D levels differed significantly among the three groups of participants; sub-analysis showed that healthy individuals had higher vitamin D levels when compared with patients with and without DFU, while vitamin D levels did not differ between patients with and without DFU (17.9 ± 6.7 vs. 19.8 ± 8.7 ng/mL, P = 0.329, respectively). More than half of patients with DM with or without DFU had vitamin D levels <20 ng/ml. A positive correlation was found between vitamin D and sun exposure duration in participants without DFU. In conclusion, although serum vitamin D levels did not differ between people with and without DFU, the prevalence of deficiency and insufficiency was high in both groups in a Mediterranean country. This finding highlights the need for screening and supplementation with vitamin D in individuals with DM.

This study examined the effects of orange juice (OJ) supplemented with vitamin D3 (2000 IU) and probiotics (Lacticaseibacillus casei Shirota and Lacticaseibacillus rhamnosus GG, 10⁸ cfu/mL) on cardiometabolic risk factors in overweight and obese adults following a Westernized-type diet. Fifty-three high-risk individuals were randomly assigned to one of two groups. Over 8 weeks, one group consumed a vitamin D3 and probiotic-enriched OJ and the other regular OJ (control). Diets remained unchanged and were documented through food diaries. Measures of metabolic and inflammatory markers and blood pressure were measured at the start and end of the study. Post-intervention, the enriched OJ group showed the following significant metabolic improvements (without changes in triglycerides, inflammation, or central blood pressure): reduced fasting insulin, peripheral blood pressure, body weight (−1.4 kg 95% CI: −2.4, −0.4), energy (−270 kcal 95% CI: −553.2, −13.7), macronutrient (dietary fat −238 kcal 95% CI: −11.9, −1.0; carbohydrates −155 kcal 95% CI: −282.4, −27.3; sugars −16.1 g 95% CI: −11.9, −1.0) intake, and better lipid profiles (total cholesterol −10.3 mg/dL 95% CI: −21.4, 0.9; LDL-C −7 mg/dL 95% CI: −13.5, −0.5). The enriched OJ led to weight loss, less energy/macronutrient consumption, improved lipid profiles, and increased insulin sensitivity after 8 weeks in those following a Westernized diet, thus indicating potential benefits for cardiometabolic risk. This study was a part of FunJuice-T2EDK-01922, which was funded by the EU Regional Development Fund and Greek National Resources.

Background and objectives: Non-alcoholic fatty liver disease (NAFLD) is spreading at alarming rates, representing a serious public health problem, and it is the most common cause of chronic liver disease. This study aims to evaluate the effects of time-restricted feeding (TRF) along with a hypocaloric Mediterranean Diet (MD) on body weight and biochemical indices. Methods: This 12-week, open-label, randomized controlled trial [NCT05866744] consists of three interventional groups following a personalized diet (1500-2100 kcal/day): control group (MD without time restriction), early 14:10 TRF, and delayed 14:10 TRF. Anthropometric measurements and biochemical analyses are carried out at baseline and 12 weeks. Results: We recruited sixty NAFLD patients with a mean body mass index (BMI) of 31.8 ± 0.8 kg/m² and a mean age of 51.05 ± 2.74 years, out of whom twenty-one (10 males, 47.6%) have completed the ongoing trial (control n = 7, early TRF n = 6, delayed TRF n = 8). There was no difference in body weight between the groups at 12 weeks, but each group lost significant body weight compared to baseline (control: 6.3%, p = 0.015; early and delayed TRF: 8%, p = 0.004, and p = 0.001, respectively). The three groups differed in total cholesterol, triglycerides, and low-density lipoprotein cholesterol levels at 12 weeks. Significant decreases in BMI, waist circumference, hip circumference, fat mass, and systolic and diastolic blood pressure were observed in all groups. Additionally, in the control group, there was a decrease in fasting insulin, homeostatic model assessment for insulin resistance (HOMA-IR), alanine aminotransferase, and controlled attenuation parameter derived from elastography; while in the early TRF group, there was a tendency for lower glycated hemoglobin A1c. Finally, in the delayed TRF group, fasting glucose, gamma-glutamyl-transferase, and alkaline phosphatase were improved compared to baseline. There was no difference in pleasure rate between the three interventions at baseline or 12 weeks. Discussion: These preliminary data show that 14:10 TRF led to clinically significant weight loss (>5%), mainly via fat mass loss, and to an improved lipid profile, regardless of the time restrictions placed on food intake. Consequently, TRF could be an alternative weight loss strategy for individuals with NAFLD.