Effects of Ketogenic Diet on Body Composition and Performance in Soccer Players

Study Overview
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Brief Summary
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A ketogenic diet (KD) is a nutritional approach, usually adopted for weight loss, that restricts daily carbohydrates under 30 g/day. KD showed contradictory results on sport performance, whilst no data are available on team sports. The investigators will investigate the influence of a KD on different parameters in soccer players

Detailed Description
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Sixteen semi-professional soccer players will be randomly assigned to a ketogenic diet (KD n=8) or to a western diet (WD n=8). Diets contain the same amount of protein (1.8g/Kg body weight/day). Body weight and body composition will be measured by dual energy x-ray absorptiometry (DXA) and bioelectrical impedance analysis (BIA). Resting energy expenditure (REE), respiratory exchange ratio (RER), cross sectional area (CSA) and isometric muscle strength of quadriceps, counter movement jump (CMJ) and yoyo intermittent recovery test will be measured.

Official Title
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Effects of a Very Low Carbohydrate Ketogenic Diet on Body Composition, Muscle Strength, Muscle Area, Metabolism and Performance in Semi-professional Soccer Players

Conditions
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Athletic Performance

Intervention / Treatment
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* Other: Western diet
* Other: ketogenic diet


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria semiprofessional soccer players male Exclusion Criteria: body fat percentage over 32%, (determined via dual energy X-ray absorptiometry DEXA), cardiovascular, respiratory, gastrointestinal, thyroid or any other metabolic diseases, weight change more than 2 Kg over the last month, adherence to special diets, use of nutritional supplements (except a daily multivitamin-mineral) use of medication to control blood lipids or glucose and goal-keepers.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 30 Years

Sexes Eligible for Study
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Male

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: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: It is single blind, parallel arms study
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Ketogenic diet<br>Ketogenic diet: less than 30 g/day of carbohydrate. Subjects can eat beef, veal, poultry, fish, raw and cooked vegetables without restriction, cold cuts such as dried beef, eggs and seasoned cheese (parmesan), ketogenic pasta (selected with a ketogenic ratio of 4:1), fruits with the lowest glycemic index (blueberry, raspberry), raw nuts and seeds, ghee butter, plant oils and fats from avocado, coconut and olives | Other: ketogenic diet<br>* Subjects in this group will follow a low carbohydrate ketogenic diet<br>|
| Active Comparator: Western diet<br>The western diet (WD) is composed mainly of whole cereals (spelt, rye, oat) and pseudo-cereals (buckwheat, quinoa, amaranth), whole grain pasta, potatoes, meet, fish, vegetables, fruit, legumes, olive oil, milk and red wine (at most 1 glass per day). It ensure a constant energy and macronutrient balance: protein 1.8g x Kg-1 x body weight-1 x day-1, (30%), fats 20-25% and carbohydrate 50-55%. | Other: Western diet<br>* Subjects in this intervention will follow a normal western diet<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fat body mass | Body composition with DEXA: we measure body fat mass in grams. | 4 weeks | 
| lean body mass | Body composition with DEXA: we measure lean body mass in grams. | 4 weeks | 
| Visceral Adipose tissue (VAT) | Body composition with DEXA: VAT in grams | 4 weeks | 
| Total body water | We will use a BIA to calculate totally body water and intracellular and extracellular water in liters | 4 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| resting energy expenditure (REE) | Measured through gas analyzer in ml/02/kg min | 4 weeks | 
| respiratory ratio (RR) | Measured through gas analyses (ratio between CO2 and O2) | 4 weeks | 
| specific performance | Yoyo intermittent recovery test level 1: in seconds | 4 weeks | 
| lower limb power | squat jump test: height of the jump in cm | 4 weeks | 
| quadriceps muscle area | muscle area measured in cm2 through ultrasound | 4 weeks | 
| quadriceps muscle thickness | muscle thickness measured cm through ultrasound | 4 weeks | 
| quadriceps strength | isometric contraction measured in N, the normalized per muscle area (N x cm2) | 4 weeks | 
| quadriceps strength per area | the strength of isometric contraction (outcome 10) normalized per muscle area (Outcome 7). Expressed as (N x cm2) | 4 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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ketogenic diet, western diet, soccer, sport performance, muscle mass, body composition