Objective: The aim of the study was to evaluate hormone level, nutrition status, and energy expenditure of patients with laparoscopic sleeve gastrectomy (LSG). Materials and Methods: Twenty female patients, who underwent a LSG operation, were subjected to testing. The body analysis and biochemical parameters of these patients were determined before and after the surgery. The patients' appetite status and food consumption were monitored during the follow-up. Results: The percentage of fat in the body, weight, and body mass index (BMI) of the patients decreased (p < 0.05). Physical activity level and total energy expenditure (TEE) increased in the postoperative period (p < 0.05). The patients' appetite score decreased in the first postoperative month (p < 0.05). Total values of energy, carbohydrate, and fat consumption of patients decreased (p < 0.05). Fasting blood glucose and triglyceride level decreased in the follow-up period (p < 0.05). In the postoperative period, the levels of thyroid stimulating hormone (TSH) and ghrelin hormone decreased compared to the preoperative period (p < 0.05). There was no correlation between the change in ghrelin hormone and TSH level among the follow-ups and body weight, BMI, and weight loss (p > 0.05). Conclusion: While there is no clear correlation of weight loss to TSH and ghrelin expressions, hormonal changes and TEE remain very dynamic in the early months after surgery. This study prospectively characterizes such changes.