You may have heard that portion sizes served up by restaurants have gone up dramatically over the last several generations. Now, a new report shows that such "portion inflation" is not just confined to restaurants. A study published this week in the Annals of Internal Medicine shows that the average portion sizes in today’s cookbooks have increased by nearly 40 percent in calories per serving in the past 70 years for nearly every recipe reviewed, accounting for an extra 77 calories per serving.

In addition to surveying several cookbooks the study looked more in depth at one particular book that has been a mainstay of American kitchens since the 1930s. Of the 18 recipes that appear in all seven versions of the cookbook (including the most recent 2006 edition), 17 of them have increased in calories per serving. The increases are partly attributable to an increase in the total calories in each recipe (now an average of 567 calories) and to larger portion sizes. One chili recipe demonstrates both such increases: in 1936, the recipe made 14 servings at 228 calories each, while the "same" recipe in the 2006 edition makes 10 servings at 576 calories each.

Several recipes did not change ingredients at all, but portion sizes as much as doubled from the original 1930s recipe. For example, some brownie and cookie recipes that used to make 30 servings now make only 15 from the same amount of batter.

The increases in calorie content and portion size are likely related to the growing affluence of the United States since the 1930s. Recipes that formerly included cheaper, less calorie-dense ingredients like beans and rice now call for meats and fats. Portion sizes may have gotten larger as people became able to afford larger servings.

People who are trying to manage their weight are often told by doctors and nutritionists to eat out less and cook at home more often. The current study suggests that people who are cooking at home using modern recipes may not be cutting their calories as much as they think. However, most excess calories in the American diet still come from food eaten outside the home, according to nutrition experts.

If you are trying to manage your weight, the researchers suggest that you halve the portion size as soon as you cook something from a modern cookbook. Just put the other half away before it even makes it to your plate, where you could end up eating it without even thinking about it. According to the study authors, such "mindless eating" is a large part of the reason why increasing portion sizes – both at restaurants and in the home – are dangerous.

Want to learn more about how to manage your weight sustainably? Read the Healia Health Guide on Weight Management for tips on portion control and ways to avoid mindless eating. To share your story with a community of people who are also trying to manage their weight, join the Healia Health Community for Weight Management. For more on nutrition, join the Healia Health Community on Diet and Nutrition.

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