Lemons are a good source of Vitamin C, which is essential for proper metabolism. They also contain flavonoids, which have been shown to help reduce belly fat. However, there is no evidence that drinking lemon water will directly lead to reduced belly fat. To lose weight and reduce belly fat, it is important to create a calorie deficit by eating fewer calories than you burn off through physical activity. While adding lemon water to your diet may help with weight loss, it is not a magical solution and should be combined with other healthy lifestyle choices.