Diabete Mellitus, Hypertriglyceridaemia, Obesity & Overweight
Conditions
Keywords
low_carbohydrate diet, type 2 diabetes, T2D, Obesity, metabolic indexes, hypertriglyceridaemia
Brief summary
Type 2 diabetes is often accompanied by high blood triglycerides and excess weight, and diet plays a central role in managing these conditions together. The purpose of this study is to compare the effects of two moderate low-carbohydrate diets - one higher in protein and one higher in fat - against a standard diet, on blood sugar control, blood lipids (especially triglycerides), body weight, and blood pressure in adults with type 2 diabetes, hypertriglyceridemia, and overweight or obesity.
Detailed description
This is a three-arm, open-label, randomized controlled trial conducted at a diabetes clinic in Tehran, Iran. Eligible patients - adults with type 2 diabetes, moderate hypertriglyceridemia, and overweight or obesity (BMI 25-35 kg/m²) - will be enrolled through consecutive sampling and randomly assigned in a 1:1:1 ratio to one of three 12-week dietary interventions: a moderate low-carbohydrate, high-protein diet; a moderate low-carbohydrate, high-fat diet; or a standard diet consistent with usual clinical recommendations. No placebo is used, given the nature of the intervention. The primary objective is to determine and compare changes in glycemic indices - HbA1c and fasting blood glucose - before and after the 12-week intervention, both within each of the three groups and between groups. Secondary objectives include comparing changes in lipid profile (triglycerides, total cholesterol, LDL-C, and HDL-C, with triglyceride reduction considered a key outcome of interest), anthropometric indices (body weight, BMI, and waist circumference), and systolic and diastolic blood pressure across the three groups. The study will also evaluate the level of dietary adherence in each group - measured through monthly self-reported adherence questionnaires and 24-hour dietary recalls - and examine how adherence relates to the observed changes in glycemic, lipid, and anthropometric measures. The incidence of diet-related side effects or adverse events will be compared across groups during the 12-week intervention and during a subsequent 30-day follow-up period. Doses of participants' existing medications for diabetes, blood lipids, and blood pressure will be kept constant throughout the study wherever clinically safe to do so, in order to isolate and attribute observed changes to the dietary intervention itself rather than to changes in medication. Participants will be contacted monthly by phone for adherence support and safety monitoring, and will have blood samples (fasting glucose, HbA1c, and full lipid profile), body weight, waist circumference, and blood pressure measured at baseline and again at the end of the 12-week intervention, followed by one additional phone contact one month after the intervention ends to assess general well-being and any delayed adverse events (without repeat laboratory or anthropometric measurement at that final contact). Applied objectives of the study include generating local, high-quality randomized-trial evidence to support individualized dietary choices (protein-focused versus fat-focused low-carbohydrate approaches) for Iranian patients with type 2 diabetes and hypertriglyceridemia, with attention to macronutrient quality (complex/fiber-rich carbohydrates, predominantly plant-based protein, unsaturated fats) consistent with the Iranian dietary pattern; assessing real-world dietary adherence and identifying barriers and facilitators relevant to clinical practice; and providing preliminary evidence that could inform future, longer-duration studies (6-12 months) examining potential reductions in medication requirements and the durability of metabolic improvements. Given the short 12-week intervention period, the trial is not designed to draw conclusions about long-term sustainability of effects.
Interventions
OTHERHigh-Protein Low-Carbohydrate Diet
A calorie-restricted (500 kcal/day below baseline needs) diet providing 40% of energy from complex carbohydrates, 30% from fat (20% unsaturated with a 4:1 MUFA/PUFA ratio, 10% saturated), and 30% from protein (15% plant-based), delivered over 12 weeks as 5 individualized daily meals.
OTHERHigh-Fat Low-Carbohydrate Diet
A calorie-restricted (500 kcal/day below baseline needs) diet providing 40% of energy from complex carbohydrates, 45% from fat (35% unsaturated with a 4:1 MUFA/PUFA ratio, 10% saturated), and 15% from protein, delivered over 12 weeks as 5 individualized daily meals.
OTHERStandard diet
A calorie-restricted (500 kcal/day below baseline needs) standard diet providing 55% of energy from complex carbohydrates, 30% from fat (20% unsaturated with a 4:1 MUFA/PUFA ratio, 10% saturated), and 15% from protein, delivered over 12 weeks as 5 individualized daily meals.
Sponsors
National Nutrition and Food Technology Institute
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
NONE
Intervention model description
Participants are randomized in a 1:1:1 ratio to one of three parallel 12-week dietary arms: a moderate low-carbohydrate high-protein diet, a moderate low-carbohydrate high-fat diet, or a standard diet.
Eligibility
Sex/Gender
ALL
Age
30 Years to 70 Years
Healthy volunteers
No
Inclusion criteria
* Diagnosed with type 2 diabetes mellitus for at least 6 months * Fasting serum triglycerides between 200-399 mg/dL * Body mass index (BMI) between 25 and 35 kg/m\^2 * Age between 30 and 70 years * If taking medication for diabetes, dyslipidemia, or hypertension, dose stable for at least 8 weeks prior to enrollment * Able to follow the prescribed diet * Willing and able to provide informed consent
Exclusion criteria
* Fasting triglycerides of 400 mg/dL or higher, or lower than 200 mg/dL * HbA1c greater than 10.5% * eGFR less than 30 mL/min/1.73m\^2 * Type 1 diabetes or rare metabolic disorders * Severe renal, cardiac, or hepatic disease, or active pancreatitis * Established cardiovascular disease (myocardial infarction, stroke, coronary angioplasty or bypass surgery, or heart failure) * Pregnancy, breastfeeding, or planning pregnancy during the study * Psychiatric disorder or social circumstances that would prevent adherence to the dietary protocol * Change in dose or type of diabetes, lipid-lowering, or blood pressure medication within 8 weeks before enrollment or during the study * Use of weight-loss medications, protein supplements, or probiotics * Body weight change greater than 3% within the past 6 months * Withdrawal of consent to continue participation
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Change in fasting serum triglyceride (TG) level | Baseline to Week 12 |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in glycated hemoglobin (HbA1c) | Baseline to Week 12 | — |
| Change in fasting blood glucose (FBS) | Baseline to Week 12 | — |
| Change in total cholesterol | Baseline to Week 12 | — |
| Change in LDL-C | Baseline to Week 12 | — |
| Change in systolic blood pressure | Baseline to Week 12 | — |
| Change in diastolic blood pressure | Baseline to Week 12 | — |
| Change in body weight | Baseline to Week 12 | — |
| Change in BMI | Baseline to Week 12 | — |
| Change in waist circumference | Baseline to Week 12 | — |
| Level of dietary adherence | Baseline to Week 12 | Assessed monthly throughout the 12-week intervention |
| Incidence of diet-related adverse events | From baseline through the 12-week intervention and a subsequent 30-day follow-up period | — |
Contacts
CONTACTzeynab kavyani, PhD student
Outcome results
None listed