Based on science, I would say no. My theory is yes. If you drink water…and replace it for what every other beverage you are consuming there will be a calorie net loss. In other words, if you drink a gatorade a day and the rest water. 50 calories (14g of which are sugar). multiply by the serving size in the container (4) = 200 calories – cut that out for a week and subsitute for water theres 1400 calories deducted over the course of a week. That is almost cutting half a pound a week of calories. So essentially I suggest progressively subsituiting water for beverages (coffee, juice, sports beverages) It will contribute to a lot in the long run…believe me it has done wonders!
Fuel the Movement
I think water is one of the most overlooked components when dealing with weight loss. Replacing other fluids, as Jason suggested, is a powerful tool in reducing the amount of calories consumed on a regular basis.
Beyond fluid substitutions, water does have physiological impacts on the ability to lose weight. Proper hydration is essential in one’s ability to perform optimally in the gym, or even in daily life. This is important in one’s ability to couple nutrition and exercise in a weight loss program. Not only that, the body will oxidize fat as a fuel source more efficiently when properly hydrated.
I could name countless benefits of adequate hydration and it’s importance in weight loss, sport performance, and general health. Quite possibly the only time water won’t help someone with weight loss is if they are already adequately hydrated (which a majority of the population is chronically dehydrated).
Taken from NASM Essentials of Personal Fitness Training
Water is the soup of life. It constitutes approximately 60% of the adult human body by weight…Consuming an adequate amount of water will benefit the body in the following ways.
Endocrine gland function improves
Fluid retention is alleviated.
Liver functions improve, increasing the percentage of fat used for energy.
Natural thirst returns.
Appetite decreases significantly.
Metabolic functions improve.
Nutrients are distributed throughout the body.
Body-temperature regulation improves
Blood volume is maintained.
My guess would be yes, water helps with weight loss.