Actually, a low saturated fat diet isn't a good idea. The type of fat is what's important, not whether it's saturated or not. Salmon has a lot of saturated fat, but it won't make you gain weight unless you eat a ton of it. Fat is more complicated than that. And while spicy foods do produce heat which warms up the body, it's unlikely to really speed the metabolism much and some people who aren't used to hot herbs might experience gastric distress. Diuretics are not healthy -- the water just comes back, and if this person is starting an exercise program the last thing she wants is temporary weight loss by flushing out water. Trying to lose weight fast by messing with digestion just won't last.
There are several foods that act as metabolisers. Diuretics also (these reduce your fluid retained). Spicy food with cayenne pepper, a diuretic ingredient like caffeine or tea, ginger and garlic also boosting your circulation. As for the upper body then really use that area hard whilst having a low salt, low sat fat diet and youll see results
It's not what you eat, it's what you shouldn't eat, which is the same as non-vegetarians -- simple carbs, which turn to sugar quickly and are stored as fat if not burned. Many vegetarians around the world have a nice soft middle because they eat so much white flour and potatoes and the like. You need to make sure you get your protein. And then you need to exercise.
try Grains , red peppers, green tea ,and lentils