Protein, Fiber, and Metabolic Syndrome - The PROFIMET Study
Condition: Overweight; Obesity; Metabolic Syndrome
MeSH terms: Overweight; Metabolic Syndrome; Syndrome
Study type: Interventional

Summary: 
      Randomized controlled single-blinded intervention study in 111 overweight and obese subjects
      with risk factors of developing type 2 diabetes, with the aim to investigate effects of
      isoenergetic high cereal fiber as compared with high protein diets over 6 and 18 weeks.

      Proof of principle study with analysis according to study protocol, investigating whether
      isoenergetic high cereal fiber and high protein diets with comparable fat contents, if
      adhered to and after exclusion of known confounders such as changes in body weight, intake of
      drugs with known effects on insulin sensitivity, or relevant changes in physical activity,
      indeed affect insulin sensitivity.
    

Detailed description: 
      This is a randomized controlled single-blinded intervention study in 111 overweight and obese
      subjects with risk factors of developing type 2 diabetes, with the aim to investigate effects
      of isoenergetic high cereal fiber versus high protein diets over 6 and 18 weeks. We also
      investigate effects of a combined high-cereal-fiber/high-protein (mix) diet, and effects in a
      control group. All diets are based on foods from plants and whey products commonly assumed to
      be healthy. This trial is designed as a proof of principle study focusing on participants
      that are likely to adhere to the respective isoenergetic diets, in order to show whether high
      protein versus high cereal fiber diets indeed affect insulin sensitivity, as indicated by
      epidemiological observations. Study participants will receive intensive and regular
      nutritional advice in order to achieve the respective dietary targets. Dietary adherence of
      the participants will be supported by providing tailored dietary supplements in all four
      groups, twice daily over 18 weeks. Supplements are provided for twice daily consumption for
      all participants in all four dietary intervention groups, throughout the 18-wk intervention
      (each of the participants will be instructed to consume a total 252 portions of tailored
      supplements during the intervention, which will handed to the participants in sealed single
      portions at weeks 0, 3, 6 and 12, totalling 63 portions at each occasion). The packaging of
      the sealed portions for the 4 intervention arms do not indicate the type of dietary
      intervention for the participant, but are coded for identification by the supplier. Energy
      contents of the supplements are considered when calculating individual energy intake.
      Supplements have been specifically designed for this intervention study, in order to
      facilitate achieving dietary targets. A 6 week strictly controlled isoenergetic study period
      (regular group and individual sessions, daily food diaries/FFQs over the first 6 weeks with
      adaptation of food intake, if necessary, as indicated by direct analysis of FFQs and food
      protocols, and by weighing the participants; 3-day food protocols at weeks 0, 6, 12, and 18;
      various biomarkers of dietary adherence) will be followed by a further 12 week ad libitum
      period, with ongoing intake of the respective diet including the supplements, but no further
      dietary advice. The primary outcome measure is the detection of diet-induced changes in
      insulin sensitivity during weight maintaining isoenergetic conditions. Secondary outcomes are
      changes in factors that may explain potential diet-induced alterations of insulin
      sensitivity. During the 12-weeks ad libitum period we will further investigate potential
      effects of the respective diet on changes in body weight, body composition and biomarkers
      related to energy intake. Participants will be re-invited for anthropometric measurements and
      measurement of biomarkers in blood (18 weeks after completion of the study), as well as for
      taking a second muscle tissue biopsy (subset of participants that agreed to this procedure).
    

Intervention name(s): control diet, supported by dietary supplement twice daily; high cereal fiber diet, supported by dietary supplement twice daily; high protein diet, supported by dietary supplement twice daily; diet moderately high both in cereal fiber and protein, supported by dietary supplement twice daily
Intervention type(s): Other; Other; Other; Other
Intervention description(s): control diet, see above; high cereal fiber diet, see above; high protein diet, see above; MIX diet, see above
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Basic Science
Keywords: parameters of metabolic syndrome