Impact of Whey and Soy Protein Ingestion in Conjunction With Energy Restriction in Overweight/Obese Individuals

Study Overview
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Brief Summary
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It is known that dieting (restricted energy intake) without resistance training leads to a reduced metabolic rate, and the loss of both fat and muscle mass. When exercise is not included in a period of restricted energy intake, the degree to which muscle mass is lost is highly dependent upon protein consumption. Whey protein is a high quality protein isolated from milk and is known to stimulate new protein synthesis for all proteins in your body. Previous research has established that the consumption of whey protein has been correlated with retaining muscle mass while stimulating fat loss. However, the mechanisms behind these findings is still unknown. The purpose of this study is to establish a mechanistic underpinning to the efficacy of whey protein versus soy protein and a carbohydrate control (maltodextrin), in promoting fat mass loss and lean mass retention during a period of short-term controlled dietary energy deficit (-750 kcalories/day).

Official Title
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Molecular Events Underpinning Changes in Tissue Metabolism With Whey and Soy Ingestion in Energy Restriction in Overweight/Obese Adults

Conditions
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Obesity

Intervention / Treatment
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* Behavioral: Weight loss
* Dietary Supplement: Soy
* Dietary Supplement: Whey


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 35 to 55 years old Moderately Obese/Overweight (body mass index > 25 and < 42 kg/m2) Healthy Non-smoker Exclusion Criteria: Suffer from type 2 diabetes, hyperlipidemia, or thyroid dysfunction Taking medications Having an unstable weight in the past 4-6 months, or dieting at some time during the past 6 months Taking weight loss products or aids (including energy drinks)

Ages Eligible for Study
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Minimum Age: 35 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Placebo Comparator: Control<br>Carbohydrate & 750 kcal dietary restriction while they receive a daily supplement (2 x 25 g) of maltodextrin (no protein) for 14 days. Weight loss. | Behavioral: Weight loss<br>* -750kcal/d<br>|
| Experimental: Whey<br>Whey protein & 750 kcal dietary restriction while they receive a daily supplement (2 x 25 g) of WPI for 14 days. Weight loss. | Behavioral: Weight loss<br>* -750kcal/d<br>Dietary Supplement: Whey<br>* 2 x 25g/d WPI<br>|
| Experimental: Soy<br>Soy protein & 750 kcal dietary restriction while they receive a daily supplement (2 x 25 g) of SPC for 14 days. Weight loss. | Behavioral: Weight loss<br>* -750kcal/d<br>Dietary Supplement: Soy<br>* 2 x 25g/d SPC<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle protein synthesis rate and lipolytic rate as measured using stable isotope and glycerol infusions. |  | After 14 day dietary intervention | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transcriptomic changes (via gene profiling) associated with the effects of whey on lipogenic and lipid oxidative genes, and protein synthetic pathways in muscle. |  | After 14 days of dietary intervention | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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obesity, overweight, muscle, protein, muscle protein synthesis, muscle protein breakdown, whey, soy, caloric restriction