Metflex: The Effectiveness of a Dietary Intervention

This study is testing the effectiveness of a dietary intervention by means of measuring the change in RQ upon a hyperinsulinemic euglycemic clamp challenge and by means of measuring the kinetic responses of multiple PF markers (including RQ) to an acute mixed meal challenge before and after a 6-week dietary intervention. The challenges will be applied to investigate whether the kinetic response is a better measure for health and wellbeing when compared to fasting (baseline) levels. In addition, several measures that reflect perceivable benefits like mood, quality of life, sleep quality, cognitive and physical performance will be assessed in a first exploratory attempt to link (changes in) PF to consumer perceivable benefits.

Subjects will be randomly allocated to a low glycemic load diet or a 'Western' diet for 6 weeks. Before and after the intervention several measurements will take place. The low glycemic load diet will be high in polyphenols, protein, vegetables, pulses, fibres and nuts, and low in glycemic carbohydrates. All these dietary factors have been shown to improve glycemic control and/or to reduce metabolic syndrome risk factors.


Eligibility Criteria:
Inclusion Criteria:

* Signed informed consent
* Men and postmenopausal women: ≥ 50 and ≤ 70 years at the start of the study
* Body mass index (BMI) ≥ 25.0 and ≤ 35.0 kg/m2
* Healthy (as determined by dependent physician): no medical conditions which might affect the study measurements, absorption, metabolism and distribution (including diabetes type 1 and type 2, gastrointestinal dysfunction, gastrointestinal surgery and inflammatory diseases) as assessed by physical characteristics and health and lifestyle questionnaire
* Fasting blood glucose value ≤ 6.9 mmol/litre at screening
* Waist circumference \>94 cm for males, \>80 cm for females
* Maximum 2.5 hours of moderate to vigorous physical activity per week (during last 3 months)
* Agreeing to be informed about medically relevant personal test-results by a physician
* Willing to comply to study protocol during study
* Accessible veins on arms as determined by examination at screening

Exclusion Criteria:

* Reported participation in another nutritional or biomedical trial three months before the pre-study examination or during the study
* Blood donation in the past three months
* Reported participation in night shift work two weeks prior to pre-study investigation or during the study. Night work is defined as working between midnight and 6.00 AM;
* Consumption of \> 21 alcoholic units for males, \> 14 alcohol units for females in a typical week;
* Reported use of any nicotine containing products in the six months preceding the study and during the study itself;
* Reported dietary habits: medically prescribed diet, slimming diet, vegetarian;
* People who are familiar with an allergy or intolerance to any of the provided food products
* Reported weight loss or weight gain (10%) in the last six months prior to the pre-study screening;
* Clinically relevant abnormalities in clinical chemistry at screening (to be judged by the study physician);
* Being an employee of Unilever or the collaborating research departments in Maastricht University Medical Centre (MUMC+);
* Taking medication, which may interfere with study measurements, as judged by the responsible physician;
* Subjects, who do not want to be informed about unexpected medical findings, or do not wish that their treating physician is informed.