The second major cause of working out but not losing weight is a poor diet. You cannot overcome a bad diet with working out even if you spend hours at the gym. Thirty minutes of running burns 400-500 calories approximately. This is maybe two pieces of cheese pizza. A breakfast of doughnuts and expensive coffee can take away all the hard work you put in at the gym. Sure, it's fine to sometimes have a meal of whatever you want. It's the constant poor food choices that lead to a stagnant weight. When your co-workers bring in cookies and brownies to share every day you simply have to decline. If the feelings of these people are hurt, so be it. You have a bigger goal than stroking the ego of the brownie person. Stick to 2200 calories a day for men and 1800 for women on most days if you want to be successful in changing your life.