Help uplift your friend in their time of need. If your friend wants to achieve a worthy goal such as losing weight, giving up smoking, or taking up a new skill, offer them your whole-hearted support. Tell them it's a good idea and go out of your way to provide them with the information or assistance they need.
For example, if your friend wants to lose weight, you can help by not indulging when you're around them and tempting them. Heck, you could join them!