Vegetarian High Protein Weight Loss Diets

Summary

This study aims to investigate the mechanistic processes involved in protein-induced satiety/satiation during weight loss in humans.

Thsi study will investigate:

* How do high-protein weight loss (HPWL) diets rich in meat or soya based protein sources impact on profile of 'motivation to eat' both within a day and between days ?
* Do biomarkers of satiety alter differentially on meat or soya HPWL diet, as measured by monitoring alteration in plasma amino acids and gut-related hormones ?
* How does a vegetarian and meat-based weight loss diet impact on nitrosamine excretion in faecal samples, as an indicator of faecal toxicity?

Previous work has indicated that high-protein (30% protein) weight loss diets are more satiating (produce less hunger) than normal protein WL diet (15% protein) or a diet supplemented with few amino acids. In previous work, a mixed source of protein has been used, mainly from meat (beef, chicken, fish). These types of diets have been criticised because of the potential negative side effects, including our own work on gut health. It might be that alternative vegetable sources of protein could fulfil the diet remit, to be satiating and yet still allow weight loss, and maintain a healthy gut.

Design -within subject, randomised cross-over design after day 3. Each subject acts as their own control and will receive each treatment. 18-20 subjects to participate.

Length of time - Conduct the two nutritional interventions over a period of 14 days, in order to reduce effects due to an acute change in nutritional intake.

PROTOCOL Days 1- 3 - Normal Protein Maintenance diet (NP- MTD, 3 days)

1. st ARM Days 4-17 - randomised to High Protein-Weight loss-Meat (HP-Soya,14 days),
2. nd ARM Days 18-31 - randomised to High Protein-Weight loss-Soya (HP-meat,14 days),

Conditions

• Obesity

Interventions

OTHER

High Protein-Weight loss-Soy diet

• The high protein (HP) weight loss diet will be fed to 100% resting metabolic rate (RMR) on a 5 day rotation menu, fed as three meals a day, 30% protein, 30% fat and 40% carbohydrate; the soya version based on soya protein or soya-tvp (textured vegetable protein).

OTHER

High Protein-Weight loss-Meat

• The high protein (HP) weight loss diet will be fed to 100% resting metabolic rate (RMR) on a 5 day rotation menu, fed as three meals a day, 30% protein, 30% fat and 40% carbohydrate; the meat version will be based on chicken and beef meat.

Sponsors & Collaborators

• University of Aberdeen

  lead OTHER

Principal Investigators

• Alexandra M Johnstone, PhD · Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, Scotland, UK,

• Wendy R Russell, PhD · Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, Scotland, UK,

• Silvia Gratz, PhD · Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen, Scotland, UK,

• Graham Horgan, PhD · Biomathematics and Statistics Scotland, Aberdeen, Scotland, UK

Study Design

Allocation

RANDOMIZED

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

MALE

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2009-12-31

Primary Completion

2010-12-31

Completion

2010-12-31

Countries

• United Kingdom

Study Locations