I would try to eat more healthily because eating certain foods are a huge magnet to toxic waste and gas. This creates more pollutions and destroys the o-zone. Another thing it to take my bike instead of car or use a hybrid or an electric car if it is to far ( my destination) for a bike. Cooking food in my house with an oven is MUCH better for the clean air as well for the coal and charcoal used for grill, and wood for fires, causes a massive pinpointed area of smoke and destroy the air causing bug leaks of hydrogen in the air molecules.
Bears eat plants such as berries, and plants get their energy from the sun. So his energy source's energy source is sunlight, which also makes it his energy source