Banana diet, water spray in stores, and diet and cancer

Publication Date: September 28, 2009 Contact: Alice Bender, (202) 328-7744 

by Karen Collins, MS, RD, CDN

American Institute for Cancer Research 

Q: What is it about bananas that makes the Banana Diet so successful?

A: Actually, stories of short-term weight loss without data from controlled studies aren’t grounds for calling this diet “successful.” Bananas provide fiber and nutrients that make them a healthful part of a balanced diet, but don’t expect them to provide any special power to promote weight loss. The Banana Diet has gained Internet fame for supposedly aiding quick weight loss. However, people’s reported weight loss could have come from other banana diet rules, that include avoiding all ice cream, alcohol, evening snacks and all beverages other than water with meals. Arbitrary rules make popular diets work in the short-term, but people often return to old eating habits once they get tired of the absolute rules. One problem with the Banana Diet is that it limits breakfast to bananas (70 to 140 calories each) that may promote immediate weight loss, but in the long run can sabotage your efforts. Long-term studies suggest that eating a small proportion of your daily calories in the morning increases the tendency to overeat later in the day and is more likely to hurt than help weight control. Successful weight control comes from avoiding excess calories in ways to that you can live with long-term. 

Q: When grocery stores spray produce with water, does that reduce their nutrient value?

A: Grocery stores mist certain fruits and vegetables to keep them from wilting and losing moisture. It is true that when vegetables are cooked or soaked in large amounts of water, certain vitamins will leach out into the water. Research is limited on grocery store misting, but it does not give reason to worry that it has negative effects. In fact, in at least one early study, misting even helped retain vitamin C in broccoli. Misting is mainly beneficial for lettuce, broccoli, green onions, cucumbers and fresh herbs that wilt easily without humidity. Others (such as onions, garlic, berries and cauliflower) should not be misted and deteriorate with too much moisture. 

Q: Can diet lower risk of lymphoma as much as it does other cancers?

A: We still have much to learn about lymphoma's link to diet. The strongest evidence at this time is the increased risk posed by being overweight. Excess body fat increases inflammation through the body and seems to affect immune function. In one study, obesity increased risk of non-Hodgkin’s lymphoma 36 to 59 percent in women and men, respectively. The mostly plant-based diet recommended to reduce overall cancer risk may also be helpful in reducing risk of lymphoma, though much of the evidence at this point is not strong. Increasing vegetables, especially cruciferous vegetables such as broccoli, may be helpful; probably because of their phytochemicals that stimulate enzymes involved in the activation and deactivation of carcinogens, as well as their impact as antioxidants. Excessive amounts of meat and/or fat (especially saturated or animal fat) may increase risk, but the evidence is tentative. Some studies show increased risk with high dairy consumption, but it’s important to consider that a “high” consumption of foods depends upon the population studied. For example, in a Swedish study, increased risk related to dairy consumption was seen in those consuming more than six-and-a-half servings daily, far above what would be "high" in the U.S. As research progresses we should know more, but for now we can most reliably place greatest emphasis on weight control and on balanced, plant-based eating for optimal effects on immune system and overall lower cancer risk.

###

The American Institute for Cancer Research (AICR) is the cancer charity that fosters research on the relationship of nutrition, physical activity and weight management to cancer risk, interprets the scientific literature and educates the public about the results. It has contributed more than $87 million for innovative research conducted at universities, hospitals and research centers across the country. AICR has published two landmark reports that interpret the accumulated research in the field and is committed to a process of continuous review. AICR also provides a wide range of educational programs to help millions of Americans learn to make dietary changes for lower cancer risk. Its award-winning New American Plate program is presented in brochures, seminars and on its Web site, www.aicr.org. AICR is a member of the World Cancer Research Fund International.