Background and Objectives: Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease primarily affecting hair follicles, characterized by painful nodules, abscesses, and sinus tract formation. Recent evidence suggests that weight management and nutritional factors may influence HS symptoms. This cross-sectional case–control study aimed to assess the impact of body composition and nutritional factors on HS severity. Materials and Methods: We included 50 patients with HS and 50 matched controls comparable in body mass index (BMI), sex, and age. The data collected included 3-day food records, a food frequency questionnaire, 24 h physical activity records, Mediterranean Diet Adherence Screener (MEDAS) scores, body composition, and anthropometric measurements. The macronutrient and micronutrient intake, as well as dietary glycemic index (GI), were analyzed. HS severity was assessed using the Hurley staging system and the International Hidradenitis Suppurativa Severity Score System (IHS4). Results: HS patients exhibited significantly lower adherence to the Mediterranean diet and a higher dietary GI compared to controls. Their micronutrient intake was also reduced, while the consumption of junk food, dairy products, and nightshade vegetables was more frequent. The MEDAS scores and physical activity levels were negatively correlated with the IHS4 scores, while higher anthropometric measurements, dietary energy, protein, total fat, and GI showed positive correlations. The Hurley stage was negatively correlated with the MEDAS scores and positively correlated with the GI and visceral fat. In multiple regression analysis, the MEDAS score emerged as the primary variable associated with disease severity. Conclusions: These findings suggest that an increased adherence to the Mediterranean diet, intake of food with a lower GI, and maintaining an ideal body weight may positively affect HS management. Long-term studies are warranted to corroborate our findings.