Should I eat before a morning workout?

If you're heading out on a very hard or long training session, then yes, it is going to be beneficial to top off energy stores after a night's fast. If the training is short or not a key performance session, you can likely complete the session without extra fuel. When working out on empty, you might not feel as energised as usual, but that's normal. However, if you feel faint or dizzy, stop and eat something. Fasted workouts can provide adaptations in the body that might lead to enhanced performances later on when the correct fuel is provided.

I have a very low metabolism, is there any way to improve it? I eat half the amount of other people and still don't lose weight.

The problem could be that you are not eating enough. If you eat less calories than your BMR plus activity levels then your metabolism can slow down. If you calculate how many calories you should be eating using a BMR calculator then you can see whether you are actually eating enough. Also, we would recommend getting your thyroid hormone levels checked to ensure you do not have an underactive thyroid. It's a simple blood test and will be useful to rule this out. If you did have a thyroid issue then eating a very low carbohydrate diet could slow down your thyroid further so also bear this in mind. Finally, doing regular exercise will help to speed up your metabolism, so try to do at least 30 minutes a day. A brisk walk would be enough.

How do I stop craving unhealthy snacks like chocolate?

If you are struggling with cravings for sweet foods this may relate to blood sugar balance. The best way to keep your blood sugar level balanced is to eat what is called a low Glycaemic Load (GL) diet and avoid, as much as you can, simple sugars and refined foods (i.e. cakes, biscuits, sweets and chocolate). Our suggestion include: Eating small, frequent meals that contain slow releasing carbohydrates, healthy fats and protein, avoid missing meals or leaving long gaps between eating, and replace sugars and refined carbohydrates with whole grains.