This scenario is no different than how will power works. When summoned, it can do wonders. For example, you're working towards a New Year's resolution of decreasing body fat, so when you go out to eat with friends, you are able to decline dessert even though others at the table are having it. However, if you store cookies and chips in places you pass frequently, such as your cupboard at home or at your desk, then you will likely fall prey to eating them at some point.
Will power is successful in fat loss when it is an occasional tool used. It is absolutely necessary, but it will likely fatigue and fail like the muscles in the opening example if needed too frequently. The point here is to avoid the reliance on will power if you hope to attain your goal. Here are a few ideas on how to do so (sticking with the idea of trying to lose fat):
- If you live alone, throw out any foods you shouldn't be eating. If you live with others, tell your housemates about what you are trying to do in the hopes that they will help by not buying such foods or hiding/locking them away.
- If you go to lunch with coworkers and they typically choose restaurants with poor food selections, ask them to go to a place that provides you with more choices or perhaps you should start eating with a new crowd or bring your own lunch in (which is probably best).
- In general, inform as many people as possible about your goals and efforts. Hopefully they will make an effort to not bring undesired foods around your desk or to your home.