can you lose weight on a diet without exercising too?

Yes, you can, certainly. But there are down-sides to trying it that way. Firstly, because of the effect of dieting, it's possible to affect your muscle mass -- it's not uncommon for people to diet and lose muscle as part of the weight that they drop, and exercise can help to off-set that.

Secondly, exercise is a booster to your weight loss anyway; you need to balance it right, though. Aerobic exercise will help you to lose weight steadily, while heavier weight-work will build muscle, but do less to directly burn fat (it needs too much energy too quickly, so the body quickly turns to using reserves of carbohydrate instead). However, weight exercise does boost _meta_bolism for a while afterwards too.

Last, but not least, exercise is beneficial for its own sake. It boosts health and fitness, and while dieting can help to negate the negative effects of being overweight, it's not a powerful positive effect for health in the way that exercise can be, especially for heart health.

On top of this, exercise is critical for body shape - you can weigh exactly the weight you want to, but if you haven't done the exercise, then the weight will be distributed wrongly and you won't have the build you want.

I've found that the secret to exercise, though, is just to find a way to make it more fun. Games are easier than workouts, and DDR is one of the easiest ways to get in exercise and have fun. It does look a bit ridiculous in public if you're not good at it already, but if you have a home game system - even a PC - you can find a way to play it, and a dance-mat is a very cheap piece of exercise equipment to buy!