1. McBurney, Michael I. PhD, FACN


Human beings seem to have limited ability to perceive calories consumed in liquid form. Scientific studies show that people do not reduce their food energy intake when including calorie-containing versus calorie-free beverages in their diet. Given the incidence of obesity around the world, it may be prudent to advise people to (1) drink fluids to maintain hydration and (2) choose calorie-free or lower calorie beverages to reduce total calorie intake


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Although the increased incidence of obese and overweight children and adolescents1 observed since 1984 seems to have stabilized at 11% and 32% between 1999 and 2006, the lifelong impact of obesity on health, economics, and quality of life is an important public health issue. In her review, Allman-Farinelli2 concludes that public health policy should be structured to reduce sugar-sweetened soft drink (soda) consumption to address global obesity and associated increased risk of developing metabolic syndrome and type 2 diabetes mellitus.


Energy consumption is unarguably important in achieving energy balance and maintaining a healthy body weight. However, is there significant scientific agreement to establish a public policy targeting soda consumption to address obesity? Or does the science support a public health approach whereby guidance should address calories from all liquid sources, that is, all beverages?


There is a substantial body of evidence that human beings do not compensate when eating for calories consumed in liquid form.3,4 Long-term interventions (10 weeks) show that habitual consumption of caloric beverages leads to significantly increased daily energy intake, weight gain, and body mass index in adults when compared with those consuming noncaloric beverages.5,6 Rolls et al7 reported that lunch meal calories were not affected by the ingestion of 8 or 16 oz of lemonade with or before (30 or 60 minutes) lunch. However, total energy intakes were significantly greater when the 42 participants drank sucrose-sweetened lemonade (vs aspartame-sweetened lemonade, water, or no beverage). In a similar study, DellaValle et al8 offered 48 women a test lunch without a beverage (control) or with a beverage consisting of 360 g of water, diet soda, regular (caloric) soda, orange juice, or 1% fat milk. Lunch meal energy intake was nonsignificantly lower when caloric beverages (regular soda, juice, and milk) were consumed, and total energy intake was significantly increased when compared with no-beverage, diet soda, and water treatments.8 Although food intake (kilocalories) at a test meal was unaffected by beverage portion size or energy content, more total calories were consumed when drinking regular soda (caloric) than diet soda or water.9 Mourao et al10 conducted a crossover challenge study in 120 adults where beverages and solid foods were matched for macronutrient content and calories. They found that the inclusion of a caloric beverage in a lunch meal led to greater daily energy intake compared with customary intake or days when a solid food with similar macronutrient and caloric content was ingested. Monsivais et al11 had 37 adults consume isocaloric soda beverages sweetened with sucrose, high-fructose corn syrup with 42% or 55% fructose, 1% fat milk, diet soda, or no beverage 2 hours after a standard breakfast and 2 hours before a cafeteria lunch. Pairwise comparisons showed that the 3 sugar conditions did not differ from each other or the milk; however, all 4 caloric beverages differed significantly from the diet soda and no-beverage conditions.11 A meta-analysis of randomized control trials found a significant reduction in total energy intake (15%) when aspartame-sweetened soft drinks were compared with nonsucrose controls such as water.12 Murphy et al13 reported that mean energy intakes by milk consumers were significantly greater than energy intakes by milk nondrinkers for all groups of children except boys aged 6 to 11 years. Moreover, more than 50% of flavored milk drinkers aged 2 to 5 years consumed whole milk rather than reduced-fat flavored milk.13 Flavored milks have been suggested as a means to positively affect calcium, phosphorus, and fiber intakes by replacing soda and fruit drink consumption without increasing added sugar intakes.14 However, this study showed that children consuming more than 240 g of flavored milk per day consumed more milk, soft drink, fruit juice, and fruit drink and, therefore, more liquid calories than did nonconsumers of milk. Females 12 to 19 years who consumed soda (regular and diet) and milk had the highest average energy intakes (1,982 +/- 62 kcal/d), whereas those who do not drink milk and soda had the lowest energy intakes (1,593 +/- 92 kcal/d).15 From these studies, it can be concluded that people do not accurately compensate food energy intake for beverage calories. Second, if the goal is to reduce weight gain, it is important to distinguish between caloric and noncaloric beverages when providing dietary guidance.


Nutrition guidance was simpler when policy could focus on emphasizing nutrient density in the context of energy balance. However, because of the increasing incidence of obesity, the 2005 Dietary Guidelines for Americans16 has 2 messages: (1) "consume fewer calories, be more active" and (2) "make wiser choices within and among food groups." Rather than targeting soft drinks to address obesity, the science supports a recommendation to choose lower energy choices within the entire consumer-packaged beverage group. Just as with other food groups, people should be encouraged to consume fewer liquid calories as consumer-packaged beverages, that is, calorically sweetened (regular) carbonated sodas, cordials, "energy" drinks, "sports" drinks, sugar-sweetened iced teas, fruitades, fruit juices, fruit punches, "specialized" coffees, and dairy-based beverages. After all, from an energy balance perspective, an 8-oz glass of juice or regular soft drink containing 70 to 90 kcal is not the lowest energy choice, nor the highest (Table 1). Fortunately, advances in food science have generated many lower calorie and often nutrient-dense food and beverage options. Classically defined food groups are no longer the sole or often primary source of essential nutrients.17 Because of the lifelong impact of weight gain and associated chronic diseases, especially among children, dietary guidance needs to first focus on energy balance. Given the overriding issue of obesity, guidance to address nutrient inadequacies, that is, calcium, should guide individuals to lower calorie choices, especially when it comes to liquid calories, which seem to be invisible but are not once ingested.

Table 1 - Click to enlarge in new windowTable 1. Comparison of the Nutrient Composition (per 8 fl oz) of Different Beverages

In summary, to address obesity and the contribution from beverages, people might be encouraged to follow these recommendations:


1. Control calorie intake to manage body weight. Choosing calorie-free or lower calorie beverages, that is, "diet" options, may reduce total daily energy intake.


2. Drink fluids to maintain normal hydration and avoid beverages that provide calories. If you drink caloric beverages, do so in moderation.


3. Engage in regular physical activity and reduce sedentary activities to promote health, well-being, and a healthy body weight.





1. Ogden CL, Carroll MD, Flegal KM. High body mass index for age among US children and adolescents, 2003-2006. JAMA. 2008;299:2401-2405. [Context Link]


2. Allman-Farinelli MA. Do calorically-sweetened soft drinks contribute to obesity and metabolic disease? Nutr Today. 2009;44:17-20. [Context Link]


3. Malik VS, Schulze MB, Hu FB. Intake of sugar-sweetened beverages and weight gain: a systematic review. Am J Clin Nutr. 2006;84:274-288. [Context Link]


4. McKiernan F, Hollis JH, Mattes RD. Short-term dietary compensation in free-living adults. Physiol Behav. 2008;93:975-983. [Context Link]


5. Tordoff MG, Alleva AM. Effect of drinking soda sweetened with aspartame or high-fructose corn syrup on food intake and body weight. Am J Clin Nutr. 1990;51:963-969. [Context Link]


6. Raben A, Vasilaras TH, Moller AC, Astrup A. Sucrose compared with artificial sweeteners: different effects on ad libitum food intake and body weight after 10 wk of supplementation in overweight subjects. Am J Clin Nutr. 2002;76:721-729. [Context Link]


7. Rolls BJ, Kim S, Fedoroff IC. Effects of drinks sweetened with sucrose or aspartame on hunger, thirst and food intake in men. Physiol Behav. 1990;48:19-26. [Context Link]


8. DellaValle DM, Roe LS, Rolls BJ. Does the consumption of caloric and non-caloric beverages with a meal affect energy intake? Appetite. 2005;44:187-193. [Context Link]


9. Flood JE, Roe LS, Rolls BJ. The effect of increased beverage portion size on energy intake at a meal. J Am Diet Assoc. 2006;106:1984-1990. [Context Link]


10. Mourao DM, Bressan J, Campbell WW, Mattes RD. Effects of food form on appetite and energy intake in lean and obese young adults. Int J Obesity. 2007;31:1688-1695. [Context Link]


11. Monsivais P, Perrigue MM, Drewnowski A. Sugars and satiety: does the type of sweetener make a difference? Am J Clin Nutr. 2007;86:116-123. [Context Link]


12. Bellisle F, Drewnowski A. Intense sweeteners, energy intake and the control of body weight. Eur J Clin Nutr. 2007;61:691-700. [Context Link]


13. Murphy MM, Douglass JS, Johnson RK, Spence LA. Drinking flavored or plain milk is not positively associated with nutrient intake and is not associated with adverse effects on weight status in US children and adolescents. J Am Diet Assoc. 2008;108:631-639. [Context Link]


14. Johnson RK, Frary C, Wang MQ. The nutritional consequences of flavored-milk consumption by school-aged children and adolescents in the United States. J Am Diet Assoc. 2002;102:853-856. [Context Link]


15. Bowman SA. Beverage choices of young females: changes and impact on nutrient intakes. J Am Diet Assoc. 2002;102:1234-1239. [Context Link]


16. US Department of Health and Human Services, US Department of Agriculture. Dietary Guidelines for Americans, 2005. 6th ed. Washington, DC: US Government Printing Office; January 2005. Accessed June 17, 2008. [Context Link]


17. US Department of Agriculture national nutrient database for standard reference, release 20. USDA Agricultural Research Service nutrient data laboratory nutrient lists. Accessed June 17, 2008. [Context Link]

Press "One" if You Want Your Child to Eat Right


Imagine turning the technology era's most annoying invention-voice-response telephone systems-into something good. Researchers did exactly that in a new study on the use of interactive voice-response counseling to offer nutrition tips to families with obese children.


Although the 200 obese or overweight children in the study sponsored by Kaiser Permanente Colorado started out with roughly similar body mass index scores, children whose parents completed at least 6 interactive voice response counseling calls ended the study with slightly lower body mass indices than did children in the 2 other intervention groups. The researchers assigned families randomly to 1 of 3 groups. One group received a work book designed to help children increase physical activity and consumption of fruits and vegetables. Another group received the workbook plus 2 small-group sessions with a dietitian. The third group received all of the above and 10 counseling sessions using interactive voice-response technology. The no-counseling groups reduced consumption of sugared drinks by 26 to 28 oz per week after a year. In comparison, the group that also had telephone counseling showed a decrease of 36 oz per week.


Children in all groups slightly increased their daily servings per day of fruit. Changes in physical activity were hard to gauge because many children refused to wear an accelerometer to measure how much they moved. After parents used the voice-activated system, researchers say that children "did not gain weight at the same rate." Stay tuned to see if later studies confirm these findings.


Source: American Journal of Preventive Medicine

Calcium May Protect Against Colorectal Cancer Only in Presence of Magnesium


Understanding the relationship between calcium and magnesium may lead to new avenues of personalized prevention for colorectal cancer. High magnesium intake has been associated with low risk of colorectal cancer. Calcium supplementation has been shown to inhibit colorectal carcinogenesis, although high calcium may simultaneously be preventing the body from absorbing magnesium. According to the researchers, there may be something about these 2 factors combined-the ratio of one to the other-that might be at play.


In a large clinical trial, researchers found that supplementation of calcium reduced the risk of adenoma recurrence only if the ratio of calcium to magnesium was low and remained low during treatment. The risk of colorectal cancer adenoma recurrence was reduced by 32% among those with a baseline calcium-to-magnesium ratio below the median in comparison to no reduction for those above the median.


It remains to be seen if other studies confirm these findings.


About 1 in 18 individuals will develop colorectal cancer in their lifetime, and 40% will die within 5 years of diagnosis, mainly because of diagnosis at a late stage. The understanding of how dietary factors affect colorectal cancer may lead to the prevention of cancer recurrence and possibly prevention of the initial cancer.


Source: American Association for Cancer Research International Conference on Frontiers in Cancer Prevention Research