Portion Size─Primary Tool to Control Obesity

• Large soft drink sizes increase consumption, and thereby contribute to obesity. Portion size labeling may help consumers to select more appropriate food portions. ¹

• Food and beverage portion sizes are related to childhood and adult obesity. Portion sizes increased significantly over the past 30-y period and increases in pizza were particularly pronounced in the last decade [176 kcal (736 kJ).  Portion sizes continue to grow for selected foods. Fast-food chains appear to be linked with less healthful portion size increases for selected foods.²

• Energy from eating occasions including pizzas and soft drinks increased, as did the proportion of energy from these foods in an eating occasion.² Portion sizes increased across all food sources (stores, restaurants, and fast foods) for soft drinks and pizzas, especially French fries at fast-food locations. ²

• Increased energy intake occurs when snacks are offered in larger portion size, regardless of energy density. Snack portion size may be an environmental strategy that can reduce excessive energy intake in children.³

• Reducing portion size  of a particular item in an all-you-can-eat environment results in reduced intake of that food for most individuals, and that reducing PS reduces Plate waste.⁴

• The impact of portion size differs among obese and lean individuals. Obese individuals consume 40% (334 kcal) more of the entree in response to the large portion condition (P < 0.05), while lean individuals’ intakes do not differ (P < 0.56). People who consume large portions also has large  bite size.⁵

• Increasing the portion size of a vegetable served as a first course can be an effective strategy for increasing vegetable consumption in children and adults to achieve the  recommended vegetable intakes and facilitate weight management.⁶  Serving more vegetables, either by adding more or substituting them for other foods, is an effective strategy to increase vegetable intake at a meal. However, to moderate meal energy intake, vegetables should be low in energy density (Most Indian vegetable dishes are overcooked in liberal amounts of unhealthy oil or liberal amounts of coconut meat or milk and therefore rich in calories as well as unhealthy fat). Furthermore, the substitution of vegetables for more energy-dense foods is more effective than simply adding extra vegetables.⁷ 

• At very young ages, the increase in overweight may be driven in part by a shift in eating patterns towards larger portion size of energy-dense and nutrient-poor foods.⁸ 

• Increasing the portion size of energy-dense entrees has been shown to increase children’s energy intake during a meal. Conversely  serving larger portions of more healthful foods, such as fruits and vegetables may decrease intake of less healthful foods.⁹ Thus variations in portion size can be used strategically to help children achieve the recommended intake of fruits.⁹ 

• Portion-size estimation is an important component of weight management. Literacy and numeracy skills may be important for accurate portion-size estimation. Lower literacy skills were associated with less accuracy when participants were asked to serve a single serving. Opportunities may exist to improve portion-size estimation by addressing literacy.¹⁰

• The term portion size is used differently by food manufacturers, regulatory agencies, and consumers. Consumers associated portion size more with daily nutrient requirements than with an ideal quantity for a satiating meal .¹¹

• Heightened food-cue reactivity might present an under-explored risk factor for overeating, and becoming overweight, and/or maintaining an overweight body shape.¹² 

Sources

1. Vermeer WM, Steenhuis IH, Leeuwis FH, Bos AE, de Boer MR, Seidell JC. View the label before you view the movie: A field experiment into the impact of Portion size and Guideline Daily Amounts labelling on soft drinks in cinemas. BMC Public Health. Jun 6 2011;11(1):438.

2. Piernas C, Popkin BM. Food Portion Patterns and Trends among U.S. Children and the Relationship to Total Eating Occasion Size, 1977-2006. J Nutr. Jun 2011;141(6):1159-1164.

3. Looney SM, Raynor HA. Impact of portion size and energy density on snack intake in preschool-aged children. J Am Diet Assoc. Mar 2011;111(3):414-418.

4. Freedman MR, Brochado C. Reducing portion size reduces food intake and plate waste. Obesity (Silver Spring). Sep 2010;18(9):1864-1866.

5. Burger KS, Fisher JO, Johnson SL. Mechanisms behind the portion size effect: visibility and bite size. Obesity (Silver Spring). Mar 2011;19(3):546-551.

6. Spill MK, Birch LL, Roe LS, Rolls BJ. Eating vegetables first: the use of portion size to increase vegetable intake in preschool children. Am J Clin Nutr. May 2010;91(5):1237-1243.

7. Rolls BJ, Roe LS, Meengs JS. Portion size can be used strategically to increase vegetable consumption in adults. Am J Clin Nutr. Apr 2010;91(4):913-922.

8. Lioret S, Volatier JL, Lafay L, Touvier M, Maire B. Is food portion size a risk factor of childhood overweight? Eur J Clin Nutr. Mar 2009;63(3):382-391.

9. Kral TV, Kabay AC, Roe LS, Rolls BJ. Effects of doubling the portion size of fruit and vegetable side dishes on children’s intake at a meal. Obesity (Silver Spring). Mar 2010;18(3):521-527.

10. Huizinga MM, Carlisle AJ, Cavanaugh KL, et al. Literacy, numeracy, and portion-size estimation skills. Am J Prev Med. Apr 2009;36(4):324-328.

11. Ueland O, Cardello AV, Merrill EP, Lesher LL. Effect of portion size information on food intake. J Am Diet Assoc. Jan 2009;109(1):124-127.

12. Tetley A, Brunstrom J, Griffiths P. Individual differences in food-cue reactivity. The role of BMI and everyday portion-size selections. Appetite. Jun 2009;52(3):614-620.