Yes, Garlic & lemon are fat burning foods & zero caloric foods.
* Garlic rich in allicin,Allicin is the most potent substance found in garlic and this has been shown to not only lower blood pressure, insulin and triglyceride levels in laboratory animals fed a sugar rich diet, but also to prevent weight gain. You can take boiled garlic in any curry or mashed & mix with milk or buttermilk.
* Drinking warm water with lemon can maintain the weight reduction.
But stomach fat is very hard to reduce easily for that one should follow the very strict diet & exercise pattern. Garlic & lemon can help you to avoid extra weight & lowering the fat from the body but for belly fat- combination of weight training, cardio exercise & diet modification are more important.