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Effects of a Ketogenic Diet on Psychological Outcomes

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT04086498
Recruitment Status : Completed
First Posted : September 11, 2019
Last Update Posted : September 11, 2019
Information provided by (Responsible Party):
Antonio Paoli, University of Padova

Brief Summary:
The aim of the study is to investigate how glycemia and ketonemia variations during three different diet protocols: a ketogenic diet without any restriction on calories intake (KD), a calorie-restricted ketogenic-mediterranean diet (KEMEPHY) and a calorie-restricted mediterranean diet (MD) affect appetite, executive functions and mood in overweight young women.

Condition or disease Intervention/treatment Phase
Overweight Mood Appetitive Behavior Other: Mediterranean diet Other: KEMEPHY Other: KD Not Applicable

Detailed Description:
Fifty overweight young women with a body mass index (BMI) greater than 25 will be randomly assigned to a ten days of ketogenic diet (KD), calorie-restricted ketogenic-mediterranean diet (KEMEPHY) or Mediterranean diet (MD). All subjects will begin the prescribed diet at the beginning of their follicular phase. Body composition, fasting blood glucose and β-hydroxybutyrate (BHB), visual analogue scale (VAS) to test appetite as well as psychological tests (one mood test and two cognitive tasks) will be obtained 5 days before the beginning and on the last day of the diet-period.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 50 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: It is single blind, parallel arms study
Masking: Double (Investigator, Outcomes Assessor)
Masking Description: Raw data are encoded with 3 letters assigned to each treatment (A, B and C). Investigators and outcomes assessor do not have access to the waiting (letter-treatment)
Primary Purpose: Basic Science
Official Title: Effects of Ketonemia and Glycemia Variations During Ketogenic and Mediterranean Weight Loss Diets on Appetite Levels, Executive Functions and Mood
Actual Study Start Date : April 1, 2015
Actual Primary Completion Date : April 30, 2016
Actual Study Completion Date : June 15, 2016

Arm Intervention/treatment
Experimental: ketogenic-mediterranean diet with phytoextracts
The KEMEPHY diet (Paoli et al., 2011) is a mediterranean calorie-controlled ketogenic protocol (about 900 Kcal/day) with the use of some phytoextracts. During this protocol subjects are allowed to eat with no limits green leafy vegetables, cruciferous, zucchini, cucumbers and eggplants. The quantity of meat, eggs and fish was limited to once a day (120g of meat or 200g of fish or 1 egg). Moreover, subjects daily consumed four food supplements and liquid herbal extracts. Food supplements are high proteins (19g/portion) and very low carbohydrate (3.5g/portion) formulas simulating the aspect and taste of common carbohydrate rich foods added with dry phytoextracts (Lodi et al., 2016).
The group received a plan for a ketogenic mediterranean with herbal extracts diet

Active Comparator: Ketogenic Diet
The KD is a protocol in which all foods containing carbohydrate are excluded, whereas meat, eggs, fish, ham, green leafy vegetables, cruciferous, zucchini, cucumbers and eggplants can be eat without any limit. This protocol allows the use of oil, lemon juice (2 tbs/day), spices and aromatic herbs with a limitation of the use of saturated fats like butter, margarine and lard. Coffee, tea and herbal tea could be sweetened with sweeteners
Other: KD
The group received a plan for a low carbohydrate ketogenic diet

Active Comparator: Mediterranean Diet
The MD is a balanced calorie-controlled diet. The calorie intake was 1200 Kcal/day of which 15% were proteins, 60% carbohydrates and 25% fat. In this protocol was highlighted the use of the typical ingredients of the mediterranean tradition, such as extravirgin olive oil, vegetables, fruits, fish, lean meat and whole grain cereals.
Other: Mediterranean diet
The group received a plan for a isocaloric Mediterranean Diet

Primary Outcome Measures :
  1. Motivation to eat and appetite [ Time Frame: after 8 weeks ]
    Motivation to eat and appetite were investigated by Visual Analog Scale (Hill & Blundell, 1982) , a test formed by 6 scales. Each scale was 10 cm long and was labelled with vertical lines and numbers (from 0 to10) every cm. Participants had to choose which part of the scale better described how they felt. The scale investigated appetite, fullness, desire to eat, how much would participant eat, urgency of eating and worries about food through 6 questions. Moreover, also the unfullness index (10 - fullness) was taken into account (R. J. Stubbs et al., 2000).

  2. cognitive task1 [ Time Frame: after 8 weeks ]
    The working memory test was an adapted version of the visuo-spatial N-back (Cui, Bray, Bryant, Glover, & Reiss, 2011; Haberecht et al., 2001). It consisted in remembering the position of the letter "o" that, in each trial, could appear in different positions, since a 9-part grid divides the screen. Number of correct or incorrect answers will be counted

  3. Cognitive task2 [ Time Frame: after 8 weeks ]
    The executive function test was an adapted version of the inhibitory control task (Amodio et al., 2010; Cona, Arcara, Amodio, Schiff, & Bisiacchi, 2013) . The stimulus were letters that appear in the centre of the screen. The task was formed by two main parts. In the first one the participant had to respond when the letter x or y appeared on the screen; in the second part the participant had to answer only when x preceded y and then vice versa. Number of correct or incorrect answers will be counted

Secondary Outcome Measures :
  1. body water content [ Time Frame: after 8 weeks ]
    Body composition will be assessed by body electrical impedance analysis (BIA) that measures Total body water and intra and extracellular water in liters

  2. lean body mass [ Time Frame: after 8 weeks ]
    Body composition will be assessed by body electrical impedance analysis (BIA) that measures lean body mass in kg

  3. fat body mass [ Time Frame: after 8 weeks ]
    Body composition will be assessed by body electrical impedance analysis (BIA) that measures fat body mass in kg

  4. Mood [ Time Frame: after 8 weeks ]
    The mood test was the Italian Version of the Depression Anxiety Stress Scales-21. It was a self report measure formed by 21 items that reliably measure depression (lack of incentive, dysphoria and low self-esteem) as well as anxiety (somatic and subjective symptoms), stress (irritability, impatience, tension and arousal) and general distress (related to anxiety and depression) (Bottesi et al., 2015). The responses are given on a 4-point Likert scale, ranging from zero if "I strongly disagree" to 3 if "I totally agree".

  5. blood glucose [ Time Frame: after 8 weeks ]
    to assess diets' effects on glycaemia, capillary blood will be analyzed. We measure glucose in mg/100ml

  6. blood ketones [ Time Frame: after 8 weeks ]
    to assess diets' effects on ketonemia, capillary blood will be analyzed. We measure ketone in mol/L

Information from the National Library of Medicine

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Ages Eligible for Study:   20 Years to 35 Years   (Adult)
Sexes Eligible for Study:   Female
Accepts Healthy Volunteers:   Yes

Inclusion Criteria:

  • female sex age between 20 and 35 years,
  • 25<BMI>39.9 kg/m2

Exclusion Criteria:

  • smokers,
  • subjects under diet-treatment,
  • subjects treated for diseases such as diabetes,
  • cardiovascular diseases,
  • depression,
  • subjects doing sport more than 2 hours per week.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT04086498

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Nutrition and Exercise Lab, DSB, University of Padova
Padova, Italy, 35131
Sponsors and Collaborators
University of Padova
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Principal Investigator: Antonio Paoli, MD University of Padova

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Responsible Party: Antonio Paoli, Professor, University of Padova Identifier: NCT04086498     History of Changes
Other Study ID Numbers: KDPSY2
First Posted: September 11, 2019    Key Record Dates
Last Update Posted: September 11, 2019
Last Verified: September 2019
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: Undecided
Plan Description: Raw data of measured variables

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Antonio Paoli, University of Padova:
ketogenic diet
Mediterranean diet
executive functions
Additional relevant MeSH terms:
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Body Weight
Signs and Symptoms