Intermittent Carbohydrate Restriction in Cardiometabolic Health

Официальное название

The Effects of Intermittent Carbohydrate Restriction on Metabolic Health and Energy Balance in Adults with Abdominal Overweight and Obesity

Обзор

Metabolic conditions, such as heart disease, type 2 diabetes, and metabolic syndrome, are among the leading causes of disability and mortality worldwide. Identifying innovative lifestyle strategies to reduce metabolic risk remains a public health priority. Further research is essential to understand how low carbohydrate intake influences human metabolism and how intermittent carbohydrate restriction impacts weight loss and metabolic health markers. This study will investigate two interventions that restrict dietary carbohydrate intake on different schedules, examining their effects on metabolic health and energy balance in adults with abdominal overweight or obesity. The physiological mechanisms potentially underlying these effects will be explored by measuring a range of lifestyle and metabolic health parameters in both free-living and laboratory settings. A digital behaviour-change intervention will be incorporated after the dietary intervention to assess whether any metabolic effects can be sustained over time. The study employs a three-arm parallel-group design consisting of a two-week lifestyle monitoring phase, a four-week dietary intervention, and a four-week digital intervention, with four laboratory visits throughout each phase. During the dietary intervention, participants will be allocated to one of three groups: (i) carbohydrate restriction (\<8% of energy intake) on two consecutive days per week, (ii) carbohydrate restriction after 4 pm each day, or (iii) no dietary changes. Dietary intake, physical activity, and glucose levels will be monitored through wearable devices in free-living conditions. The digital intervention will use a mobile health application that provides individualised lifestyle recommendations and education based on data collected in free-living conditions. Laboratory-based measures will include anthropometry, body composition scans, indirect calorimetry, blood pressure monitoring, fat biopsies, and postprandial sampling of blood and expired air.

Вмешательства

• Другое 5:2 carbohydrate restriction
  Carbohydrate ingestion restricted to \<8% of energy intake on 2 self-selected consecutive days each week over 28-30 days. Ad libitum dietary amount, type and pattern followed on the remaining 5 days each week.
• Другое Early time-restricted carbohydrate intake
  Carbohydrate intake restricted to \<8% of energy intake after 4pm each day for 28 days. Ad libitum dietary amount, type and pattern followed before 4pm.

Первичные конечные точки

• Post Prandial Triglyceride Area Under the Curve (AUC) [Срок оценки: Pre and post intervention (4 weeks)]

Вторичные конечные точки (12)

• Fat Mass [Срок оценки: Pre and post intervention (4 weeks)]
• Lean Body Mass [Срок оценки: Pre and post intervention (4 weeks)]
• Fasting and Post Prandial Glucose Concentration [Срок оценки: Pre and post intervention (4 weeks)]
• Fasting and Post Prandial Insulin Concentration [Срок оценки: Pre and post intervention (4 weeks)]
• Fasting and Post Prandial NEFA Concentration [Срок оценки: Pre and post intervention (4 weeks)]
• Fasting Triglyceride Concentration [Срок оценки: Pre and post intervention (4 weeks)]
• Fasting Total Cholesterol Concentration [Срок оценки: Pre and post intervention (4 weeks)]
• Fasting LDL-C Concentration [Срок оценки: Pre and post intervention (4 weeks)]
• Fasting HDL-C Concentration [Срок оценки: Pre and post intervention (4 weeks)]
• Substrate Oxidation [Срок оценки: Pre and post intervention (4 weeks)]
• Adipose Tissue Gene Expression [Срок оценки: Pre and post intervention (4 weeks)]
• Adipose Tissue Protein Expression [Срок оценки: Pre and post intervention (4 weeks)]

Критерии участия

Критерии включения

• Waist circumference of ≥94 cm (37 inches) if male and ≥80 cm (31.5 inches) if female, or BMI above 25 kg/m2
• Fat mass index (FMI) of >6 kg/m2 for males, and >9 kg/m2 for females
• Aged between 18-65 years
• Has maintained a stable weight in the last three months (<3% change in body mass)
• Keeps track of menstrual cycle regularity or oral contraceptive use (females only)

Критерии исключения

• Has a body weight of ≥120kg
• Plans to undertake other lifestyle modifications during the study to manage weight (e.g. changes in dietary intake or activity levels)
• Current or previous eating disorder
• Diagnosed with major chronic conditions (e.g. type 2 diabetes, coronary heart disease, cancer, chronic kidney disease, etc.)
• Use of medication that may interfere with study outcomes (e.g. glucose or lipid lowering medications)
• Currently or recently pregnant (within last 6 months), planning to get pregnant or currently lactating
• Has donated more than 500ml of blood in the last 3 months prior to the initial laboratory visit
• Insufficient mental capacity or language skills to independently understand and follow the study protocol
• Dietary restrictions to ingredients in test meals (e.g. gluten and lactose)
• Has an irregular sleeping pattern (e.g. due to undertaking night-shift work)
• Any condition, concurrent intervention or behaviour deemed either to pose undue personal risk to the participant or to introduce bias into the experiment

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Да

Дизайн исследования

Распределение

Рандомизированное

Модель

Параллельные группы

Маскирование

Открытое

Основная цель

Фундаментальное исследование

Центры проведения

Великобритания · 1 центр

• University of Bath — Bath

Идентификаторы

NCT: NCT06684834 · 323721

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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