Short Answer 
Snacks are smaller and consumed more frequently between meals, while main meals are larger, more nutritionally balanced, and prepared with longer cooking times. Socially, main meals foster gatherings, whereas snacks are typically consumed casually; their primary purposes differ, with snacks providing quick energy and main meals meeting significant nutrient needs.
Step 1: Understanding Size and Frequency
Snacks are typically smaller in portion size than main meals, which are more substantial and filling. While main meals are eaten during specific times like breakfast, lunch, and dinner, snacks are consumed more frequently throughout the day. For instance, you might have snacks between meals to stave off hunger, making them a casual yet frequent part of your eating routine.
Step 2: Nutritional Composition and Preparation
Main meals offer a more balanced nutrient composition, typically including proteins, carbohydrates, and vegetables, whereas snacks can often lean towards being sugary or salty. Additionally, the preparation time differs significantly; main meals usually require longer cooking times, while snacks are often quick to prepare or can be eaten right out of the package, making them convenient for busy lifestyles.
Step 3: Social Context and Purpose
Socially, main meals often involve gatherings with family or friends, marking moments of togetherness, whereas snacks are usually consumed alone or in less formal settings. The core purpose also varies: snacks aim to ease hunger or boost energy quickly, while main meals are designed to meet substantial daily nutrient and energy needs, providing longer-lasting satiety.