The confinement due to COVID-19 generated several changes in the lifestyle of Athletes. PURPOSE: To establish changes in body composition and perception of change in food consumption and frequency in high-performance athletes during mandatory confinement of COVID-19 pandemic. METHODS: A cross-sectional analytical study with a quantitative approach was conducted on conventional and paralympic athletes. Athletes signed an informed consent; they had a nutritional assessment before and after the confinement and filled the survey for perception of changes in food consumption (PCFC). Anthropometric measurements included the five-component tissue analysis model. Bone muscle index (muscle mass/bone mass), adipose muscle index (adipose mass/muscle mass), and sum of 6 folds were considered. The PCFC survey was conducted in Google Forms. It consisted of food safety, pre-and post-confinement feeding: 7 multiple-choice questions asking the frequency of consumption and amount. Results were grouped by: Proteins, Fats, Carbohydrates, Vegetables and fruits, Ultra-processed foods, Alcohol. Answers were unified into categories: decrease, maintenance, and increase. RESULTS: The average age of the 74 athletes (33 male) was 23 years (± 5.9) years. Participants did not have limitations in accessing food. 23% of athletes decreased the frequency and quantity of protein. Fat foods increased in both quantity (31.1%) and frequency (33.8%). 33% of athletes increased the frequency of consumption of ultra-processed foods. - Anthropometric measure General Pre-confinement Post-confinement Average Diff. p* Media SD Media SD Weight (kg) 63.6 10.1 65.77 10.3 -2.04 0.000* Waist circumference (cm) 74.0 5.8 76.2 6.3 -2.18 0.000* Bone muscle index 4.2 0.55 4.3 0.56 -0.06 0.205 Sum of 6 folds 71.5 29.6 82.7 29.8 -11.25 0.000* % Body fat (yuhasz) 13.0 5.4 14.5 5.5 -1.48 0.000* Body Mass Index (BMI) km/m2 22.9 2.2 23.6 2.4 -0.708 0.000* Adipose Muscle Index 0.6 0.4 0.6 0.2 0.00 0.913 Muscle mass (kg) 29.4 6.7 30.2 6.1 -0.741 0.030 Fat mass (kg) 16.9 4.9 18.1 4.6 -1.23 0.000* CONCLUSION: COVID 19 confinement influenced the dietary patterns in performance athletes. There was an increase in all parameters related to the adipose component. Although the perceived frequency of consumption of food sources of protein decreased during confinement, it had no impact on muscle mass. The alteration of body composition could be explained by the decrease of exercise energy expenditure although the intensity of training was not measured.