Week of September 17, 2012
Contact: Alice Bender, (202) 328-7744

AICR HealthTalk
Karen Collins, MS, RD, CDN
American Institute for Cancer Research

Q: Does drinking more water really help you lose weight?

A: In some small studies, drinking 16 ounces of water before meals has helped decrease calorie consumption and improved weight loss among middle aged and older adults participating in weight loss programs. It also seemed to help them maintain their weight loss after the programs ended. We need more studies to know if this really works. If it does, it’s not clear whether it would be due to reducing hunger or if it has direct effects on metabolism. You may hear claims that drinking more water will rev up your metabolism so you lose weight by burning more calories. However, I can find only a couple controlled studies that tested this. These studies show a small increase in calorie burning after cold water was consumed. This involved a bit over 16 ounces of cold water in adults, and proportionately smaller, but still substantial, amounts in overweight children. However, in one study, the increase in metabolic rate was minimal; in the other, although the effect was larger, it was shown only briefly. Even if repeated several times a day, researchers estimate that it would result in weight loss of a couple pounds over a whole year. Other claims that drinking water supports weight loss through washing out fat are not founded on research at all. It seems more likely that if drinking water works, it does so by helping you eat less. Other studies suggest that consuming more water-rich foods may be even more effective at helping reduce calorie consumption. For example, in a study in which people consumed the same amount of water at a meal as a beverage or in soup, those who ate the water-rich soup consumed fewer calories.

Q: What do blood tests of CRP really show? Can lifestyle change it?

A: C-reactive protein (CRP) is a protein that rises with inflammation. By measuring CRP levels, the CRP test is a measure of inflammation in the body. The standard CRP test is used to diagnose and monitor treatment of short-term inflammation (such as a bacterial infection) or major inflammation of disorders like inflammatory bowel disease or an autoimmune disease. The test called hs-CRP (high-sensitivity CRP) can measure mildly elevated levels of this protein that mark chronic, low-grade inflammation linked with increased risk of heart disease, stroke and diabetes. Studies suggest that chronic low-grade inflammation may also promote cancer development by damaging our genes, increasing cell turnover and increasing development of blood vessels so cancer can spread. Levels of hs-CRP do change in response to lifestyle choices like regular exercise and not smoking. A predominantly plant-based “Mediterranean style” diet with plenty of vegetables, fruits and beans also seems to decrease hs-CRP levels. Weight control seems to be another important way to prevent or reduce inflammation. As individuals become overweight, fat cells enlarge and increase production of proteins that promote inflammation throughout the body. Overweight people who lose weight reduce CRP levels. Tests of hs-CRP are skewed by certain medications, temporary illness or chronic inflammation like arthritis, so it’s important to discuss results with your physician.

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