Glycemic and Satiety Response to Fiber and Glycemic Index of Meals in Diabetes

The aim of this study is to assess the post-prandial response of four breakfast with different content of dietary fiber and glycemic index on glycemic response and satiety in patients with type 2 diabetes.

Design study:

Single-blind crossover randomized clinical trial

Hypothesis:

A meal with high GI and high fiber content determines a lower glycemic response compared to a meal with high GI and low fiber content (fiber beneficial effect on glycemic response independent of glycemic index.

Test meals:

Four test meals isocaloric and with the same proportion of macronutrients will be evaluated (5 kcal/kg, 17% of energy provided by protein, 58% of energy provided by carbohydrates, and 25% of energy provided by fat):

Test Meal A:high glycemic index (GI= 60.3%) and high fiber content(5.88g) Test Meal B:high glycemic index (GI= 62.8%) and LOW fiber content(2.05g) Test Meal C:low glycemic index (GI= 37.0%) and high fiber content(5.75g) Test Meal D:low glycemic index (GI= 38.4%) and high fiber content(1.91g)

Outcomes:

Glycemic response: serum glucose and insulin Satiety response: serum ghrelin and subjective assessment of satiety by a specific scale for measurement of appetite in single test meal studies.

Logistic:

Patients will undergo a clinical, nutritional and laboratory evaluation for confirm the inclusion criteria and will be request to give their written informed consent.

All participants will test each meal with a mean of seven days separating the individual test days.A 12h fast will precede all the study visits.Pre-and postprandial blood samples will be draw to determine the concentrations of serum insulin and plasma glucose, and ghrelin through an antecubital cannula before and 15, 30, 45, 60, 90, 120 and 180 min after the test meals. The VAS scale will be applied in these times.

• Other: GI and fiber meals
  meals with different fiber content and glycemic index
• Other: meals
  four different meal regarding GI and fiber content

• Experimental: meal D
  low fiber and low GI
  Interventions:

  • Other: GI and fiber meals
  • Other: meals
• Experimental: meal C
  low Fiber and High GI
  Interventions:

  • Other: GI and fiber meals
  • Other: meals
• Experimental: meal B
  high Fiber and low GI
  Interventions:

  • Other: GI and fiber meals
  • Other: meals
• Experimental: meal A
  high fiber and high GI meal
  Interventions:

  • Other: GI and fiber meals
  • Other: meals

Inclusion Criteria:

• type 2 diabetes,
• HbA1c < 9%,
• BMI < 35kg/m²,
• Metformin and/or diet as treatment for diabetes

Exclusion Criteria:

• Use of insulin as diabetes treatment
• digestive disease with malabsorption
• diabetes neuropathy with gastroparesis

• Federal University of Rio Grande do Sul
• Coordenação de Aperfeiçoamento de Pessoal de Nível Superior.