## 2 Impact of GFD on Nutritional Status in CD Patients  
Several studies [5; 6; 7] analyzing large populations of Irish, North American, and Italian CD patients highlighted the risk of overweight and obesity among CD patients following GFD. [PERSON] et al. showed that, at diagnosis, 82% of celiac Italian adult patients had a normal or body mass index (BMI) \(>\) 25 kg/m\({}^{2}\), and only 10% were underweight [7]. After initiating GFD, BMI increased [7]. A recent meta-analysis confirmed these results assessing a statistically significant increase in BMI of celiac patients before and after initiating GFD (standard mean difference (SMD) 0.26; 95% confidence interval (CI) 0.17, 0.35 \(p\) < 0.001) [8]. [PERSON] et al. [9] went further, focusing on the prevalence of metabolic syndrome-defined as a combination of diabetes, high blood pressure, and obesity-in CD patients on a free diet and after GFD. Moreover, newly diagnosed patients with CD and normal BMI or overweight are likely to increase BMI one year after starting GFD. A recent study found that in 44 Asian patients with CD, metabolic syndrome was present in 11.4% of patients at diagnosis and more than 18% after one year of GFD [10]. After a median duration of 4 years of GFD, 26.3% of 130 CD patients developed a metabolic syndrome [10]. Conversely, few studies showed beneficial effects of GFD on BMI in celiac patients. A North American study demonstrated, after 2.8 years of GFD, a reduction in BMI in 16.7% of overweight CD patients and in 5.9% of obese CD patients, and an increase in BMI in 47.5% of underweight CD patients [11]. [PERSON] et al. demonstrated that the body weight and BMI of CD women were significantly lower than healthy controls [12]. This could be explained by the lower total energy intake found in the CD patients than healthy subjects [12].  
In children, a recent study showed that CD patients following GFD presented a significantly higher increase in weight and BMI compared to controls. [PERSON] et al. showed that after a minimum of one year of a GFD, CD children showed significantly higher values of fat-free mass and muscle mass [13]. The prevalence of obese CD patients at diagnosis ranges from 0% to 6%, whereas, after initiating GFD, it varies from 0% to 8.8%. On the other hand, [PERSON] et al. enrolling 120 children with CD and 100 healthy children both on a GFD for \(\geq\)2 years, showed that the nutritional status of CD children did not differ from healthy children [14]. However, a higher intake of fat and a lower intake of fiber was reported in the diet of CD children compared with controls [13]. Consequently, an in-depth nutritional status assessment seems to be necessary for children with CD. As regards celiac adolescents, after one year of GFD, body weight, BMI, fat-free mass, bone mineral density significantly decreased compared with controls [15].  
To sum up, the impact of GFD on body weight and body composition in adult CD patients remains debated, and further studies are needed. However, in children and adolescents, we understand that a suitable nutritional education program is useful to help them to accept this diet. Indeed, children and adolescents may feel deprived of appetizing products and be tempted by high consumption of commercial gluten-free, highly processed products [16]. GFPs are generally high in fat to improve their presentation and palatability and often have a greater glycemic index and a lower content of folates, iron, and B vitamins than their gluten-containing equivalents [17]. Consequently, their frequent intake may lead to an increased risk of dyslipidemia, overweight, or obesity. In the next paragraph, we sought to highlight possible associations of GFD with potential metabolic disorders and nutritional deficiencies in celiac patients.