A study published in the Journal of Nutrition analyzed data collected from more than 50,000 people aged 30 years and up. The study found that people who snacked less, avoided eating in the evening, and made breakfast their biggest meal had, on average, a lower body mass index than those who snacked more, ate later in the day, and ate big dinners.
What type of study is this?
A. Systematic review
B. Observational study
C. Intervention study
D. In-vitro study