Weight gain is often more complex than just “calories in, calories out.” From air pollution to social media stress, these unusual factors remind us a wide range of environmental, social, and biological factors influences that weight. Weight gain is often more complex than just “calories in, calories out.” From air pollution to social media stress, these unusual factors remind us a wide range of environmental, social, and biological factors influences that weight. Health and Fitness, Health Tips, Exercises & Workout Tips, Diet & Wellness | Times of India Lifestyle