Effect of Cyclical Ketogenic Diet vs. Balanced Diet on Body Composition and Performance in | Apuntes de Ciencias de la Tierra y del Medio Ambiente

nutrients

Article

The Influence of Cyclical Ketogenic Reduction Diet

vs. Nutritionally Balanced Reduction Diet on Body

Composition, Strength, and Endurance Performance

in Healthy Young Males: A Randomized

Controlled Trial

Pavel Kysel 1, Denisa Haluzíková1, Radka PetrákováDoležalová1, Ivana La ˇnková2,3,

Zde ˇnka Lacinová2,4, Barbora Judita Kasperová3, Jaroslava Trnovská2, Viktorie Hrádková3,

Miloš Mráz3, Zdenˇek Vilikus 1,* and Martin Haluzík3, 4, *

1Department of Sports Medicine, First Faculty of Medicine and General University Hospital,

12000 Prague, Czech Republic; [email protected] (P.K.); [email protected] (D.H.);

[email protected] (R.P.D.)

2Centre for Experimental Medicine, Institute for Clinical and Experimental Medicine,

12000 Prague, Czech Republic; [email protected] (I.L.); [email protected] (Z.L.); [email protected] (J.T.)

3Diabetes Centre, Institute for Clinical and Experimental Medicine, 12000 Prague, Czech Republic;

[email protected] (B.J.K.); [email protected] (V.H.); [email protected] (M.M.)

Institute of Medical Biochemistry and Laboratory Diagnostics, First Faculty of Medicine, Charles University

and General University Hospital, 12000 Prague, Czech Republic

*Correspondence: [email protected] (Z.V.); [email protected] (M.H.)

Received: 31 August 2020; Accepted: 15 September 2020; Published: 16 September 2020

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Abstract:

(1) Background: The influence of ketogenic diet on physical fitness remains controversial.

We performed a randomized controlled trial to compare the effect of cyclical ketogenic reduction

diet (CKD) vs. nutritionally balanced reduction diet (RD) on body composition, muscle strength,

and endurance performance. (2) Methods: 25 healthy young males undergoing regular resistance

training combined with aerobic training were randomized to CKD (n=13) or RD (n=12).

Body composition

, muscle strength and spiroergometric parameters were measured at baseline

and after eight weeks of intervention. (3) Results: Both CKD and RD decreased body weight, body fat,

and BMI. Lean body mass and body water decreased in CKD and did not significantly change in RD

group. Muscle strength parameters were not affected in CKD while in RD group lat pull-down and

leg press values increased. Similarly, endurance performance was not changed in CKD group while

in RD group peak workload and peak oxygen uptake increased. (4) Conclusions: Our data show that

in healthy young males undergoing resistance and aerobic training comparable weight reduction

were achieved by CKD and RD. In RD group; improved muscle strength and endurance performance

was noted relative to neutral effect of CKD that also slightly reduced lean body mass.

Keywords: body composition; ketogenic diet; strength parameters; endurance; training

1. Introduction

The last decade has been characterized by the search for alternative dietary ways to achieve

optimal body composition while maintaining or improving physical fitness and sports performance

to promote healthy lifestyle and prevent chronic diseases [

]. Current trends in sports nutrition

are increasingly reaching for the minimization of the carbohydrate component with ketogenic diet

becoming a very popular approach, in particular in endurance athletes [3,4].

Nutrients 2020,12, 2832; doi:10.3390/nu12092832 www.mdpi.com/journal/nutrients

Effect of Cyclical Ketogenic Diet vs. Balanced Diet on Body Composition and Performance in, Apuntes de Ciencias de la Tierra y del Medio Ambiente

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nutrients

Article

The Influence of Cyclical Ketogenic Reduction Diet

vs. Nutritionally Balanced Reduction Diet on Body

Composition, Strength, and Endurance Performance

in Healthy Young Males: A Randomized

Controlled Trial

Pavel Kysel 1 , Denisa Haluzíková 1 , Radka Petráková Doležalová 1 , Ivana La ˇnková 2,3,

Zde ˇnka Lacinová 2,4, Barbora Judita Kasperová 3 , Jaroslava Trnovská 2 , Viktorie Hrádková 3 ,

Miloš Mráz 3 , Zdenˇek Vilikus 1,* and Martin Haluzík 3,4,*

Abstract: (1) Background: The influence of ketogenic diet on physical fitness remains controversial.

We performed a randomized controlled trial to compare the effect of cyclical ketogenic reduction

diet (CKD) vs. nutritionally balanced reduction diet (RD) on body composition, muscle strength,

and endurance performance. (2) Methods: 25 healthy young males undergoing regular resistance

training combined with aerobic training were randomized to CKD (n = 13) or RD (n = 12).

Body composition, muscle strength and spiroergometric parameters were measured at baseline

and after eight weeks of intervention. (3) Results: Both CKD and RD decreased body weight, body fat,

and BMI. Lean body mass and body water decreased in CKD and did not significantly change in RD

group. Muscle strength parameters were not affected in CKD while in RD group lat pull-down and

leg press values increased. Similarly, endurance performance was not changed in CKD group while

in RD group peak workload and peak oxygen uptake increased. (4) Conclusions: Our data show that

in healthy young males undergoing resistance and aerobic training comparable weight reduction

were achieved by CKD and RD. In RD group; improved muscle strength and endurance performance

was noted relative to neutral effect of CKD that also slightly reduced lean body mass.

Keywords: body composition; ketogenic diet; strength parameters; endurance; training

1. Introduction

The last decade has been characterized by the search for alternative dietary ways to achieve

optimal body composition while maintaining or improving physical fitness and sports performance

to promote healthy lifestyle and prevent chronic diseases [ 1 , 2 ]. Current trends in sports nutrition

are increasingly reaching for the minimization of the carbohydrate component with ketogenic diet

becoming a very popular approach, in particular in endurance athletes [3,4].

According to current definitions, carbohydrate intake within the range of 50–150 g per day can be

described as non-ketogenic low-carbohydrate regimens [ 5 ]. Ketogenic diet is most commonly defined

by a daily carbohydrate intake below 50 g per day or energy provision from carbohydrates for up to

10% of total energy intake [ 6 ]. Out of the frequently used approaches, targeted ketogenic diet allows

carbohydrates to be consumed immediately around exercise to sustain performance without affecting

ketosis [ 7 ]. The cyclical ketogenic diet (CKD) alternates periods of ketogenic dieting with periods

of high-carbohydrate consumption [ 8 ]. The period of high-carbohydrate eating is supposed to refill

muscle glycogen to sustain exercise performance [9].

The influence of ketogenic diets on sports performance is still the topic of an ongoing debate [ 10 , 11 ]

with often conflicting results [ 12 ]. The overreaching mainstream nutrition philosophy for endurance

athletes emphasizes a carbohydrate-dominant, low fat paradigm. Under these dietary conditions,

carbohydrates are utilized as predominant fuel source to cover high volumes of aerobic exercise [ 13 ].

The appeal of low carbohydrate high fat diet for endurance athletes is likely due to the shift in fuel

utilization, from a carbohydrate-centric model with limited glycogen sources to predominant fat

utilization with much bigger and longer-lasting fat stores [ 14 ]. This metabolic shift, seen after a period

of dietary alteration, is often referred to as being “fat-adapted”, which has been well-documented

in studies since the 1980s [ 15 ]. Substantial reduction in carbohydrate intake promotes utilization of

ketones and, according to some studies, it may enhance physical performance due to minimizing

the reliance of body metabolism on carbohydrates [ 16 , 17 ] and reduce lactate deposition leading to

enhanced recovery [ 18 ]. Importantly, ketogenic diets are, in particular in the short-term run, a very

efficacious way to reduce body weight not only in physically active subjects but also in patients with

obesity, type 2 diabetes and other chronic lifestyle diseases [ 19 – 21 ]. Nevertheless, it has to be noted

that long-term compliance and efficacy of ketogenic diet is not optimal and most of the studies had

rather limited duration [19,22].

Here we performed a randomized controlled trial to compare the effect of the cyclical ketogenic

reduction diet (CKD) vs. nutritionally balanced reduction diet (RD) on body composition, muscle

strength, and endurance performance in healthy young males undergoing regular resistance training

three times/week combined with aerobic training three times/week. We hypothesized that CKD will

be more efficacious in inducing fat loss as compared to RD while maintaining aerobic performance.

To this end, we explored the effect of eight weeks of CKD vs. RD combined with regular exercise on

body composition, and measures of strength and aerobic performance.

2. Materials and Methods

Twenty-five males of various fitness levels with minimum of one-year experience in resistance

training recruited from colleges of physical education and through a website with readers interested

in fitness and diets. Inclusion criteria were as follows: age between 18 and 30 years and a minimum

one-year experience with resistance and aerobic training. Subject recruitment began in April 2019 and

lasted until January 2020. Persons interested in participating were screened to ascertain they meet the

minimum criteria for the enrollment into the study.

Exclusion criteria were current injuries or health conditions that might have affected sports

performance or put them at risk for further injuries including the presence of cardiovascular diseases,

diabetes mellitus, arterial hypertension, or any other diseases that required pharmacological treatment.

Additionally, subjects taking any performance enhancing supplements (i.e., creatine, β-hydroxy

β-methyl butyrate, caffeine, protein powder, weight gainer, thermogenics, etc.), were required to

discontinue consumption at least one week prior to baseline testing and continue abstaining from

their use for the remainder of the study. The study was approved (ethic approval code 764/18 S-IV)by