Alimentation and Diabetes in Lanzarote - ADILAN: a Pilot Trial

The purpose of this study is to compare two healthy diets (according to official Spanish guidelines) that have been shown to be effective in the treatment of type 2 diabetes in order to see if one is better than the other.

Another goal is to test the hypothesis that food choice has metabolic effects that are independent of macro/micronutrient composition, fiber content, glycemic load and weight loss in the treatment of type 2 diabetes.

There is some uncertainty with respect to the optimal dietary treatment of type 2 diabetes. In addition to energy balance, macronutrient composition, dietary fiber and glycemic load, increasing evidence suggests that the direct endocrine effects of food may be important.

In this trial, the intervention is based on two diets. The healthy diet with grains and dairy is based on whole grains, low-fat dairy, fish, shellfish, fruit, vegetables, legumes, eggs, nuts and refined vegetable oils rich in monounsaturated fatty acids (this is called "healthy diet A"). The healthy diet without grains and dairy is based on fish, shellfish, lean meat, fruit, vegetables, root vegetables, eggs and nuts, but excludes grains, legumes, refined vegetable oils, dairy products and salt (this is called "healthy diet B"). Both diets were classified as very healthy using validated nutritional software, and are considered healthy regarding macronutrient composition, fiber, mineral and vitamin intake according to the official Spanish dietary guidelines. The macro and micronutrient ratios, fiber content and glycemic load in healthy diet A and healthy diet B have been set to be equal.

The goal is to include 15 patients (\>18 years) with medical diagnosis of type 2 diabetes, with or without medication, and increased waist circumference (≥80 cm for women and ≥94 cm for men), to a cross-over trial during two periods of 4-weeks separated by a 6-week washout period.

Lunch will be served in a hospital kitchen for control of nutrient intake, while the rest of meals will be eaten at home according to specific directions.

The working hypothesis of this study is that food choice has beneficial effects on the control of glucose beyond macro/micronutrient composition, fiber content, glycemic load and weight loss.

This study will provide information on whether food choice and diet quality has greater impact than macro/micronutrient composition, fiber content, glycemic load and weight loss in glucose control in patients with type 2 diabetes, and the need to conduct a long-term trial testing our hypothesis.

Eligibility Criteria:
Inclusion Criteria:

* Medical diagnosis of type 2 diabetes
* Increased waist circumference (≥80 cm for women and ≥94 cm for men)
* Unaltered medical diabetes treatment since three months before start of study
* Stable weight (varied less than 5%) since three months before start of study
* HbA1c ≥6.0%

Exclusion Criteria:

* Creatinine \>130 μmol/L
* Change of treatment with betablocker last 3 months
* Change of treatment with thyroid hormone substitution last 3 months
* Treatment with anticoagulant medication
* Oral or injected steroid treatment
* Elevated liver enzymes (AST, ALT, ALP, GPT \> 4 times their respective upper reference value)
* Physical or psychical illness, or changes in personal circumstances that make it impossible for the patient to continue in the study