A unit based on ancestral calculations handy

Long used as a reference measure to calculate our dietary energy intake, the very notion of the calorie is today called into question by many dieticians. Exceeded value or mode phenomenon?

Calorie or actual energy expenditure?

In fact, the most complicated is not to define what a calorie is, but to measure the energy density (DE) of a meal and the expense actually needed to burn those famous calories. According to some French researchers, recently gathered at the last Annual Nutrition and Dietetics Day 1, the estimation of calories on our plate is not easy, even by professionals!

When our unconscious mind works with calories ...

Currently, the energy density of a food is counted in kcalories or kjoules per 100 grams of product. It takes into account the water content and nutrients. Thus, lipids provide 9 kcal per gram, proteins and carbohydrates 4 kcal per gram.

Fight the calorie traps

The calculation of calories is carried out according to a method put in place by the American researcher Wibur Olin Atawer at the end of the XIXe century. He calculated the energy contained in a food by burning it. His method relies on the body's energy expenditure by subtracting uric acid and organic waste. And yet, these calculations used for decades would not be right, simply because the organism does not use only "burned" foods. Considering this obsolete mode of calculation, Weight Watchers has recently modified its programs.

Other factors are to be taken into account such as the method of cooking, the digestion time or the fiber content of a given food. Finally, integrating all these values ​​into the calculation of real energy expenditure, the energy value of a food can vary from 5 to 25% of its reference value. In particular, fibers, non-energy substances, add weight and volume but not calories. They therefore contribute to reducing the energy density of a food. Thus the energy value of a food rich in fiber can increase from 2 kcal to 1.5 kcal with this new method of calculation 2.

And yet, because "the overall energy density of a meal is difficult to define, quantify and interpret, especially in human physiology and nutrition, calorie still remains a very practical value," says Xavier Leverve, scientific director " Human Nutrition and Food Safety "at INRA and Director of the Bioenergetics and Fundamental and Applied Unit at Inserm 3.

Finally, it should be noted that the energy density does not take into account the drinks consumed during the meal. "So there is nothing new about this approach, except knowing that you can actually eat more (by volume) while ingesting less energy," concludes the United States Bellisle, research director at INRA.

The evaluation of the number of calories is also questionable because of more subjective notions. According to Pierre Chandon, specialist of food psychology at the Insead of Fontainebleau, the estimation of calories is subject to three systematic and unconscious biases

In the country of calories, everything would be a history of perception ... One understands thus the difficulty to evaluate the calorie content of a meal, prepared meals or a menu taken in the restaurant.
To minimize the undesirable effects of our unconscious, it is thus recommended

Last year, the FAO (Food and Agriculture Organization of the United Nations) convened an international group of nutritionists to discuss the future of the so-called "calorie". But despite these many discoveries, these data are still not validated by the food agency. It will therefore still take some time to keep the calorie as a marker.

1 - 50th Annual Nutrition and Dietetic Day, 2 - "Energy values ​​of unavailable carbohydrate and diets: an inquiry and analysis", Livesey G. American Journal of Clinical Nutrition Vol 51, 617-637, Calories, From Plate to Cell, Xavier Leverve, Presentation at the 50th Annual Nutrition and Dietetics Day, January 2010 4 - Markers of the Validity of Reported Energy Intake, Livingstone MBE, Journal of Nutrition, March 2003 6 - Perceived calories, the impact of marketing "by Pierre Chandon, presentation at the 50th Annual Nutrition and dietetics, January 2010

The site of the 50th Annual Nutrition and Dietetic Day

The calories of foods good for health are systematically underestimated. A bias that is now reinforced by the fact that light becomes a selling point. For example, there is a greater tendency to consume 50% more light 4 products. In other words, instead of eating 100 g of normal cookies, 150 g of light cookies are put in; Health lowers all the calories of the meal. The researchers showed that the control of a dish perceived as "good for health" leads to a guilty slack on the sides: drinks and desserts contain up to 131% more calories compared to those Would have ordered with another main course 5. Calories are slightly overestimated for small portions but greatly underestimated for large portions 6. Clearly, a small portion of ice will be perceived as higher in calories than it would Is really. Conversely, if it is the whole pot that is victim of our gluttony, we will tend to largely underestimate the calories ingest. Conclusion: opt for small portions and individual shares.

To estimate calories per serving, more easily quantifiable, to opt for small portions, even if you are not satisfied if you are not satisfied, and do not take all the health claims you can Find on the packaging and examine the label (lipid content, including saturated fatty acids, carbohydrates, protein, etc.) on the scanner.) Finally, rather than focusing on the qualitative aspect (foods perceived as healthy) , Do not forget to stay reasonable on quantity!