You must be careful when chopping an onion and leaving it for use the next day: it will become toxic without feeling, as it will carry a lot of toxic bacteria that may cause infections in the stomach because of the negative discharge, which will result in food poisoning.
Try to get at least 30% of your total calories from protein. People who do this loose twice as much weight as people who ate less than 15% of their calories from protein. WHY? Because your body burns the most calories when digesting protein.