## 2 Materials and Methods  
This study included 200 overweight and obese adults (% of them are females) who participated in a cross-sectional case study. The study was conducted in two countries in southern Europe, the Republic of North Macedonia (Group 1: 100 participants, 31% male and 69% female) and Kosovo (Group 2: also 100 participants, 13% male and 87% female). All participants were enrolled in the body weight reduction program and signedconsent for their data to be used for scientific purposes, considering and respecting all GDPR principles. None of the participants dropped out of the program. The study was conducted in accordance with ethical permission (code 10-168/1 approved on 28 April 2022). The data collected for each participant were based on their (i) medical condition and family history related to overweight/obesity, (ii) dietary habits related to the intake of foods with high (snacks (salty/sweet), seeds, nuts, sweet and carbonated drinks) and low energy densities (fruits and vegetable), before the weight loss program, and (iii) anthropometric data (body height, body mass, chest, abdomen, waist, hips, biceps, and thigh circumferences) before and after 120 days of being enrolled in the program. The participants' anthropometric data were collected following the recommendation [20]. For each participant, a targeted body mass was set (which corresponds to a body mass index in the range of 24-25 kg/m\({}^{2}\)). Basic data of the participants at the beginning of the program are listed in Table 1.  
The food intake of both groups during the weight loss program based on the ketogenic diet was controlled and based on the average daily energy and nutrient intake presented in Table 2. \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Basic Information**} & \multicolumn{2}{c}{**Group 1**} & \multicolumn{2}{c}{**Group 2**} \\ \cline{2-4}  & **Male (_n_ = 31)** & **Female (_n_ = 69)** & **Male (_n_ = 13)** & **Female (_n_ = 87)** \\ \hline \multirow{2}{*}{Age (years)} & 35.3 & 37.6 & 41.8 & 38 \\  & (18–569) & (18–68) & (18–57) & (18–67) \\  & 103.3 & 78.8 & 108.4 & 91.3 \\ \multirow{2}{*}{Body mass (kg)} & (60.3–237) & (50.7–152.5) & (85.1–157.6) & (62.5–161.2) \\  & 1.76 & 1.64 & 1.74 & 1.65 \\ \multirow{2}{*}{Body height (m)} & (1.62–1.92) & (1.47–1.84) & (1.55–1.85) & (1.52–1.83) \\  & 38.3 & 33.6 & 35 & 32.8 \\ \multirow{2}{*}{Body mass index (kg/m\({}^{2}\))} & (26.3–64.3) & (25.4–63.5) & (28–49) & (25.1–54.5) \\  & 2.5 & 2.1 & 2.5 & 2.6 \\ \multirow{2}{*}{Consumed meals per day (No.)} & (1–4) & (1–4) & (2–4) & (1–5) \\  & 110.7 & 100.9 & 105.4 & 101.3 \\ \multirow{2}{*}{Waist Circumference (cm)} & (80–164) & (75–162) & (77–138) & (66–166) \\ \multirow{2}{*}{Waist-to-hip ratio} & 0.97 & 0.95 & 0.94 & 0.95 \\  & (0.91–1.05) & (0.89–1.05) & (0.85–1.03) & (0.85–1.03) \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Basic data presented as average value with corresponding range (given in the brackets) for the participants of two groups collected during the first medical visit. \begin{table}
\begin{tabular}{l c} \hline \hline
**Controlled Dietary Parameters** & **Content** \\ \hline Energy, kJ & 6280 \(\pm\) 210 \\ Proteins \({}^{\#}\), g & 136 \(\pm\) 5.6 \\ Fats \({}^{\#}\), g & 95 \(\pm\) 4.3 \\ Carbohydrate \({}^{\#}\), g & 360 \(\pm\) 1.9 \\ vitamins & 1.4 \(\pm\) 0.02 \\ Riboflavin (vit. B\({}_{2}\)), mg & 1.6 \(\pm\) 0.03 \\ Niacin (vit. B\({}_{3}\)), mg NE & 18 \(\pm\) 0.8 \\ Pantothenic acid (vit. B\({}_{5}\)), mg & 6 \(\pm\) 0.3 \\ Vitamin B\({}_{6}\), mg & 2 \(\pm\) 0.08 \\ Biotin (vit. B\({}_{p}\)), mg & 150 \(\pm\) 6.2 \\ Folic acid (vit. B\({}_{9}\)), mg & 200 \(\pm\) 10.4 \\ Vitamin B12, mg & 1 \(\pm\) 0.2 \\ Vitamin C, mg & 60 \(\pm\) 2.7 \\ Vitamin D, mg & 5 \(\pm\) 0.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Average energy and nutrient content of the controlled ketogenic diet.