Effects of a Ketogenic Diet on Psychological Outcomes

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).

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

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

Body composition will be assessed by body electrical impedance analysis (BIA) that measures Total body water and intra and extracellular water in liters

Body composition will be assessed by body electrical impedance analysis (BIA) that measures lean body mass in kg

Body composition will be assessed by body electrical impedance analysis (BIA) that measures fat body mass in kg

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".

to assess diets' effects on glycaemia, capillary blood will be analyzed. We measure glucose in mg/100ml

to assess diets' effects on ketonemia, capillary blood will be analyzed. We measure ketone in mol/L