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

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

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

Study Overview

• Status: Completed
• Conditions: Athletic Performance
• Intervention / Treatment: Other: ketogenic diet; Other: Western diet

Detailed Description

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.

• Study Type: Interventional
• Enrollment (Actual): 16
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Padova, Italy, 35131
    • Nutrition and Exercise Lab, DSB, University of Padova

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 30 years (Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: Male

Description

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.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Ketogenic diet; 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; Subjects in this group will follow a low carbohydrate ketogenic diet
Active Comparator: Western diet; 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; Subjects in this intervention will follow a normal western diet

What is the study measuring?

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

Collaborators and Investigators

• Sponsor: Antonio Paoli

Publications and helpful links

General Publications

• Rubini A, Bosco G, Lodi A, Cenci L, Parmagnani A, Grimaldi K, Zhongjin Y, Paoli A. Erratum to: Effects of Twenty Days of the Ketogenic Diet on Metabolic and Respiratory Parameters in Healthy Subjects. Lung. 2017 Feb;195(1):155. doi: 10.1007/s00408-016-9958-0. No abstract available.
• Paoli A, Bianco A, Grimaldi KA. The Ketogenic Diet and Sport: A Possible Marriage? Exerc Sport Sci Rev. 2015 Jul;43(3):153-62. doi: 10.1249/JES.0000000000000050.
• Paoli A, Grimaldi K, D'Agostino D, Cenci L, Moro T, Bianco A, Palma A. Ketogenic diet does not affect strength performance in elite artistic gymnasts. J Int Soc Sports Nutr. 2012 Jul 26;9(1):34. doi: 10.1186/1550-2783-9-34.
• Antonio Paoli A, Mancin L, Caprio M, Monti E, Narici MV, Cenci L, Piccini F, Pincella M, Grigoletto D, Marcolin G. Effects of 30 days of ketogenic diet on body composition, muscle strength, muscle area, metabolism, and performance in semi-professional soccer players. J Int Soc Sports Nutr. 2021 Sep 16;18(1):62. doi: 10.1186/s12970-021-00459-9.

Study record dates

Study Major Dates

• Study Start (Actual): May 2, 2018
• Primary Completion (Actual): October 30, 2018
• Study Completion (Actual): December 15, 2018

Study Registration Dates

• First Submitted: August 29, 2019
• First Submitted That Met QC Criteria: September 2, 2019
• First Posted (Actual): September 6, 2019

Study Record Updates

• Last Update Posted (Actual): September 6, 2019
• Last Update Submitted That Met QC Criteria: September 4, 2019
• Last Verified: September 1, 2019

More Information

Terms related to this study

• Keywords: muscle mass; body composition; ketogenic diet; western diet; soccer; sport performance
• Other Study ID Numbers: KDsoccer

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No
• IPD Plan Description: Raw data of outcomes on request

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No