NY Times: Serving Sizes Making Us Fat?

Nicholas Bakalar of The New York Times follows up on yesterday’s Associated Press coverage of a new research linking serving sizes to how much we actually consume. Bakalar provides more details on this study:
At a social gathering of 85 faculty members, graduate students and staff workers in the department of food science at the University of Illinois at Urbana-Champaign, the partygoers served themselves ice cream. They did not realize that they were also the subjects of an experiment. Half the participants were given 17-ounce bowls, and half 34-ounce bowls. In addition, half were given 2-ounce spoons to scoop out their ice cream, and half were given 3-ounce serving spoons.

With larger spoons, people served themselves 14.5 percent more, and with a larger bowl, they heaped on 31 percent more. With both a large spoon and a large bowl, the nutrition experts helped themselves to 56.8 percent more ice cream than those who used the smaller utensils. And all but three of them ate every bit of the ice cream they took.

People who used small spoons took more spoonfuls, but not nearly enough to compensate for the total amount taken by those with larger equipment.
In Eat to Live Dr. Fuhrman talks about our stretch receptors that naturally send signals to our brain when our stomachs are full. But junk foods like ice cream which lack sufficient fiber and nutrients blunt these signals and allow us to over consume large servings. Dr. Fuhrman explains:
The brain controls our dietary drive. A complicated system of chemoreceptors in the nerves lining the digestive tract carefully monitor the calorie and nutrient density of every mouthful and send such information to the hypothalamus in the bran, which controls dietary drive.

There are also stretch receptors in the stomach to signal satiety by detecting the volume of food eaten, not the weight of the food. If you are not filled up with nutrients and fiber, the brain will send out signals telling you to eat more food, or overeat.

In fact, if you consume sufficient nutrients and fiber, you will become biochemically filled (nutrients) and mechanically filled (fiber), and your desire to consume calories will be blunted or turned down. One key factor that determines whether you will be over weight is your failure to consume sufficient fiber and nutrients. This has been illustrated in scientific studies.1

How does this work in practice? Let’s say we conduct a scientific experiment and observe a group of people by measuring the average number of calories they consumed at each dinner. Next, we give them a whole orange and a whole apple prior to dinner. The result would be that the participants would reduce their caloric intake, on the average, by amount of calories in the fruit. Now, instead of giving them two fruits, give them the same amount of calories from fruit juice.

What will happen? They will eat the same amount of food they did when they had nothing at the beginning of their meal. In other words, the juice did not reduce the calories consumed in the meal—instead, the juice became additional calories. This has been shown to occur with beer, soft drinks, and other sources of liquid calories.2

Liquid calories, without the fiber present in the whole food, have little effect at blunting our caloric drive. Studies show that fruit juice and other sweet beverages lead to obesity in children as well.3

1. Lawton, C.L., V.J. Burley, J.K. Wales, and J.E. Blundell. 1993. Dietary fat and appetite control in obese subjects: weak effects on satiation and satiety. Int. J. Obes. Metab. Disord. 17 (7): 409-16; Blundell, J.E., and J.C. Halford. 1994. Regulation of nutrient supply: the brain and appetite control. Proc. Nutr. Soc. 53 (2): 407-18; Stamler, J., and T.A. Dolecek. 1997. Relation of food and nutrient intakes to body mass in the special intervention and usual care groups on the Multiple Risk Factor Intervention Trial. Am. J. Clin. Nutr. 66 (1 supp.): 366-73S.

2. Mattes, R. 1996. Dietary compensation by humans for supplemental energy provided as ethanol or carbohydrates in fluids. Physiology and behavior 59: 179-87.

3. Dennison, B. A., H.L. Rockwell, and S.L. Baker. 1997. Excess fruit juice consumption by preschool-aged children is associated with short stature and obesity. Pediatrics 99 (1): 15-22; Dennison, B.A. 1996. Fruit juice consumption by infants and children: a review. J. Am. Coll. Nutr. 15 (5 supp.): 4-11S.
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