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Thursday, August 23, 2012
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by Karen Collins
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Q: I was gradually losing weight for about six months, and now I seem stuck at a plateau. Is it true that this is probably because of slowed metabolism?
A: Some evidence shows that people may end up with a major drop in metabolic rate if they have lost large amounts of weight very quickly by doing hours of intense exercise daily while also reducing calories dramatically. But a group of experts that reviewed the literature in energy balance found that this is probably not the most common reason for the weight loss plateau so many experience. The consensus of the experts said that although calorie needs do decrease with gradual weight loss, it is not enough to stop weight loss until a person has followed a reduced calorie diet for about three to five years. More likely, the authors say, people who see a plateau at six to eight months are not continuing their initial changes in calorie consumption. Try keeping a detailed food record for a week. Include everything you eat and drink other than water; include even odds and ends outside of meals, and note all portion sizes. Often, the act of keeping a food record actually changes eating behavior. For more help, review your record with a registered dietitian who can put the information in perspective by comparing it to your calorie and nutrient needs. Or you might start by entering your food record into an online program or smart phone app that tallies what you’ve eaten and compares it to very general recommendations for weight loss in someone of your age, weight and gender. Sometimes it’s a few small changes that gradually creep in keeping calorie consumption too high to allow weight loss. Don’t take extreme measures; look for a few smart calorie cuts you think you can continue long-term while eating balanced, mostly plant-based foods that keep hunger satisfied.
Q: Eating more calories than I should won’t cause a weight problem as long as they’re largely from protein, right?
A: No, if you eat too many calories, you will add body fat, even if the calories include lots of protein. It’s true that protein is important for weight management and healthy body composition. Studies now show that protein helps keep hunger satisfied longer than either the carbohydrate or fat that we eat. What’s more, getting enough protein is important to build and maintain lean body tissue like muscle and to maintain metabolic rate, which is probably important to long-term weight control. In one controlled trial where 25 participants were required to eat similarly excessive calories, body fat increased equally in all groups, regardless of whether people were consuming low, normal or high levels of protein. Bottom line: whether your goal is to lose, maintain or gain weight, do make sure each meal totals up adequate protein from beans, nuts, seeds, whole grains and vegetables, as well as dairy and seafood, poultry and meat if you choose them. But don’t think of protein as some magic food that goes only to muscle; excess calories from any source still promote excess body fat. This is important, since the real link to increased risk of cancer and type 2 diabetes is not weight itself, but excess body fat.
Q: How are Americans doing at meeting current dietary recommendations?
A: Studies show we are still not consuming nutrient-rich plant foods like vegetables, fruits, whole grains and beans in amounts that support good health (and a healthy weight). Those foods are being pushed out because we overdo on foods high in “empty calories” from SoFAS (aka solid fats and added sugars) and alcohol. The recommendation is that total calories from “SoFAS” provide no more than five to fifteen percent of our calories. Analysis of the most recent survey of Americans’ eating habits shows U.S. men and women consume more than three times the amount of empty calories recommended as the upper limit. About one-third of these empty calories come from snacks. Although our total grain consumption meets or exceeds recommended amounts, we eat too many refined grains. Americans get only 15 percent of even the minimum recommendation of at least three servings of whole grains daily. Less than five percent of Americans get recommended amounts of dietary fiber from foods, 14 grams per 1000 calories. Another area where we don’t meet the dietary recommendations is sodium: Half of Americans are advised to limit sodium to no more than 1500 milligrams (mg) per day because they have or are at increased risk of high blood pressure, but less than two percent do so. Even for those advised to aim for a more lenient 2300 mg of sodium per day limit, less than 12 percent meet the target.
Q: I know sausage and other processed meats are linked with colon cancer risk. Is it true that they’re linked with risk of diabetes, too?
A: Yes, several large population studies now link greater consumption of processed meats with increased risk of type 2 diabetes. Processed meats are those that are salted, cured or smoked or contain preservatives (such as nitrite- or nitrate-based products). Common examples of processed meat in the United States are bacon, sausage, hot dogs, processed canned meats, ham and packaged lunchmeats. Scientists have identified several potential mechanisms that could explain the convincing link between processed meats and greater risk of colorectal cancer. Risk of type 2 diabetes increases with overweight, so processed meats’ high content of fat (and therefore calories) could explain part of the link to diabetes risk. However, even after adjusting for weight and some other aspects of eating habits, people who consume the most processed meat show at least 45 to 60 percent greater risk of developing type 2 diabetes. Researchers hypothesize that nitrite-based preservatives form nitrosamine compounds within our gut increase cancer risk, and these nitrosamines also damage the cells of the pancreas responsible for producing insulin. Another potential explanation for the diabetes link involves formation during meat processing of compounds called advanced glycation endproducts (AGEs) that seem to increase low-grade inflammation and oxidative stress and both of these conditions promote a metabolic environment that can lead to type 2 diabetes.
Q: Since potatoes supply vitamin C and other nutrients, are potato chips really so bad for you?
A: It’s true that potatoes and potato chips contain vitamin C, fiber and potassium, but here’s the difference: chips are concentrated sources of calories and sodium. A potato can supply nearly 20 to 50 percent of recommended amounts of potassium (a mineral that seems to counterbalance some of the blood pressure raising effects of sodium), as well as vitamin C and fiber. Potato chips also offer some of these nutritional benefits, but you’d have to eat several hundred more calories worth of chips to get the same levels of nutrients. And chips made from rehydrated potato flakes (chips sold in cans, for example) contain less vitamin C than others. For potatoes and chips, portion and preparation hold the key to smart choices. A one-ounce serving of potato chips – about 15 chips - typically contains a little over 150 calories with one to three grams of saturated fat. (within the average adult’s recommended daily 15-gram maximum, depending on other food choices.) In comparison, a small baked potato about two inches wide supplies about the same number of calories, but with no saturated fat; and it provide more hunger-satisfying bulk. Keep in mind though, if topped with a couple pats of butter and some regular sour cream, you’ll make that small baked potato higher in calories and saturated fat than the ounce of potato chips. Potato chips also pose the disadvantage of high sodium content. Bottom line: if you’re craving potato chips, savor a small amount occasionally. Turn to small potatoes with flavorings low in calories and sodium as the savvy way to get their nutritional benefits.
Q: If I switch my summertime treat from ice cream to sorbet, will that help with weight control or be more nutritious?
A: A half-cup of ice cream, which is the standard serving size listed on labels, usually contains 130 to 200 calories, but richer, high-fat types may contain up to 300 calories. Sorbet is a no-fat, non-dairy frozen dessert made with fruit purée or juice, sugar (or corn syrup or both), flavorings and a bit of pectin or other thickener. Calories are typically 110 to 140 in that half-cup serving. So it’s substantially lower in calories than rich ice cream, but not necessarily a lower-calorie alternative to lighter versions of ice cream. Each half-cup serving contains 5 to 9 teaspoons of sugar, which includes both the natural sugar in fruit and added sugar and high fructose corn syrup. Even when it’s made with berries or other fruits high in nutrients like vitamin C, sorbet is not necessarily a good source of those nutrients. Bottom line: The single biggest way to reduce the impact of frozen desserts on your weight is portion control. Sorbet is a refreshing treat, but for nutrition impact, top a small portion of whatever you choose with a half-cup of unsweetened fruit. You can also make a major impact by switching from ice cream as a nightly necessity to a weekly treat.
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 $95 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 website, www.aicr.org. AICR is part of the global network of charities that are dedicated to the prevention of cancer. The WCRF global network is led and unified by WCRF International, a membership association which operates as the umbrella organization for the network .The other charities in the WCRF network are World Cancer Research Fund in the UK (www.wcrf-uk.org); Wereld Kanker Onderzoek Fonds in the Netherlands (www.wcrf-nl.org); World Cancer Research Fund Hong Kong (www.wcrf-hk.org); and Fonds Mondial de Recherche contre le Cancer in France (www.fmrc.fr).
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