Effect of Diet and Physical Activity on Incidence of Type 2 Diabetes (Preview)

Inclusion Criteria:

For adults:

1. BMI>25 kg/m2
2. Pre-diabetes (The criteria from IDF (International Diabetes Foundation) for assessing pre-diabetes will be used as the formal inclusion criteria, i.e. having Impaired Fasting Glucose (IFG): Fasting venous plasma glucose concentration 5.6-6.9 mmol/l or Impaired Glucose Tolerance (IGT): Venous Plasma glucose concentration of 7.8 - 11.0 mmol/l at 2 h after oral administration of 75 g glucose (oral glucose tolerance test, OGTT). Due to potential between-lab variation (local assessments))

For children:

1. Age-adjusted value corresponding to BMI>25 kg/m2 (Cole et al. 2000)
2. Since the prevalence of pre-diabetes among children with overweight or obesity is low, it is not feasible to include exclusively pre-diabetic children (according to criteria of the IDF). Therefore insulin resistant overweight/obese children, defined as a homeostasis model assessment of insulin resistance HOMA-IR >2 , will be included.

Exclusion Criteria:

1. Use of prescription medication (including steroid inhalers and sprays), except stable antihypertensive medication, lipid lowering agents, and oral contraceptives.
2. Thyroid diseases (auto-immune related hypothyroidism is allowed inclusion, if the participant is on stable thyroxine replacement for at least 3 months)
3. Persons with any chronic disease making a 6-year survival improbable as well as other medical characteristics likely to interfere with participation in the study, including problems making participation in physical activity program risky or impossible;
4. Participants engaged in competitive sports
5. Special diets (e.g. vegan, Atkins) within 2 months prior to study start. A lacto-vegetarian diet is allowed.
6. Severe food intolerance expected to interfere with the study
7. Regularly drinking > 21 alcoholic units/week (men), or > 14 alcoholic units/week (women)
8. Drug use
9. Blood donation within the past 1 month before entering the study.
10. Self-reported weight change of >5 kg within 2 months prior to screening (baseline) assessment (week 0)
11. Psychiatric illness as defined by DSMIV or ICD10 criteria
12. Self-reported eating disorders
13. Pregnant or lactating women, or women who are planning to become pregnant within the next 36 months.
14. Persons who do not have access to either (mobile) phone or Internet (this is necessary when being contacted by the instructor's during the maintenance phase)
15. Insufficient communication with national language
16. Past or present cancer (except basalioma and squamous skin cell cancer), which in the investigator's opionion could interfere with the results of the trial
17. Previous history of bariatric surgery
18. Chronic inflammatory bowel diseases or celiac disease
19. Clinically significant active cardiovascular disease (myocardial infarction, stroke within the past 6 mo and/or heart failure)
20. Failure to reach the 8% weight reduction during the LED-phase leads to exclusion from the intervention.
21. Blood pressure is measured and those with systolic blood pressure, SBP, above 160 and diastolic blood pressure, DBP, above 100 mmHg are also excluded (participants with SBP=159 and/or DBP=99 are allowed inclusion). Well regulated BP (<140/90 mmHg) using drugs (except B-Blockers) is allowed if no change in BP and drug treatment within last 3 months.