Since 2020, the world has been immersed in a change in lifestyle (social, lifestyle, nutri-tion and physical activity patterns), due to the appearance of COVID-19 and the strict mobility measures which were implemented to prevent its spread. All these changes had a nutritional impact on people, modifying their dietary guidelines. This cross-sectional study was carried out to assess whether dietary habits, lifestyle, and adherence to the Mediterranean diet among the Spanish adult population (25–65 years old) during confinement was modified during the post-confinement period, using an e-survey through social networks, involving 510 subjects. A decrease in the intake of ultra-processed products, with a correlation between weekly food delivery orders at home and the consumption of salty snacks, sugary drinks, and processed pastries was also recorded. Most of the subjects performed physical exercise on a regular basis, maintaining the body weight in half of the participants. During the post-confinement period a substantial proportion of the population had healthy lifestyle and dietary habits, including the adequate consumption of fruits, vegetables and legumes; adequate time was spent preparing meals and the population did not regularly order food at home, which in the long term, reduced the risk of several diseases.