How Can I Better Estimate How Many Calories I Ate?

Guessing how many calories we ate in a meal is a dangerous game. Most of us terribly underestimate how much we eat –usually by up to 50%.

Think your sandwich and chips were about 400 calories? 750 is probably closer to the truth. In fact, we’ve shown that the bigger and bigger the meal, the less accurate we are in guessing how much we ate.

There are two easy solutions. One is to take our best calorie guess –and then double it. We’ll be a lot more accurate than if we stick with our first estimate.

​The second solution is to separately estimate the number of calories in each item we eat –the sandwich, the chips, the soft drink –and then add them up. We’re a lot more accurate when we estimate small amounts of food than entire meals.

Source:  Pierre Chandon and Brian Wansink (2006) Journal of Marketing Research