We all know the recommended daily allowance of calories that the government has handed us, but do you know where those amounts originate from? Do you know enough about it to trust that those are your energy needs? Because I’m telling you now, you shouldn’t.
I would recommend reading Gwyneth Olwyn’s ‘MinnieMaud Method and Temperament Based Treatment‘ and ‘I Need How Many Calories?!!‘ for an extensive and in-depth analysis of how the RDA guidelines came about, and why they are so inaccurate – complete with references. However, I understand that, although sound in science and reason, many people do show doubt in Your Eatopia and want more evidence: to which I would say, look up the references! Regardless, I am going to write this shorter article in less detail to illustrate why we all need more than that magic RDA.
The recommended daily allowance set by the government came about by using surveys that relied on self-reporting. This means, in short, that members of the population filled out the survey and the results were averaged out. The actual results were above what the RDA is now:
The FDA wanted consumers to be able to compare the amounts of saturated fat and sodium to the maximum amounts recommended for a day’s intake–the Daily Values. Because the allowable limits would vary according to the number of calories consumed, the FDA needed benchmarks for average calorie consumption, even though calorie requirements vary according to body size and other individual characteristics.
From USDA food consumption surveys of that era, the FDA knew that women typically reported consuming 1,600 to 2,200 calories a day, men 2,000 to 3,000, and children 1,800 to 2,500. But stating ranges on food labels would take up too much space and did not seem particularly helpful. The FDA proposed using a single standard of daily calorie intake–2,350 calories per day, based on USDA survey data. The agency requested public comments on this proposal and on alternative figures: 2,000, 2,300, and 2,400 calories per day.
Despite the observable fact that 2,350 calories per day is below the average requirements for either men or women obtained from doubly labeled water experiments, most of the people who responded to the comments judged the proposed benchmark too high. Nutrition educators worried that it would encourage overconsumption, be irrelevant to women who consume fewer calories, and permit overstatement of acceptable levels of “eat less” nutrients such as saturated fat and sodium. – Marion Nestle (from here)
In short, the results came up as an average of 2,350 calories, and even though that has been shown to not be enough for the average man or woman, they still went and lowered it to 2000. We also know that people under-report what they eat for numerous reasons: not knowing the accurate calorie count of food, missing out liquids and condiments, and reporting what they think they should be eating, rather than what they are eating. Even without mentioning that information on the subject of under-reporting, the NHS has written that the calorie guidelines have been underestimate by 16% due to revaluation of people’s average physical activity, including walking, breathing, and even sleeping.
To put it even more into perspective, the RDA for children aged 5-10 years old is 1800 calories. That’s for small children. When you look at that logically, growing teenagers and fully developed adults are clearly going to need significantly more than that.
Although it does not say what the calorie intake was for either groups, in one interesting study, where they studied the eating of healthy, everyday women, they found that those that were eating in an unrestrained way were eating 410 calories on average more than those who ate in a restrained way, and had a relatively lower weight, which feeds into the relatively well-researched theory that eating less actually can cause you to gain more weight due to a decreased metabolism.
When we talk about teenagers, researchers conducted a study involving more than 200 children between the ages of 8 and 17, and used a lunch buffet to give them access to unlimited food. They found that boys routinely eat more compared to girls of the same age, but the amounts that both parties ate do not fit with the RDA that they are supposed to follow. They found that boys in their mid-teens ate an average of 2,000 calories during the lunch hour, which they thought made most sense due to the age that puberty hits most boys. Their calorie requirements appear to shoot up drastically in late puberty (between the ages of 14 and 17). They found that with prepubescent children, the boys averaged nearly 1,300 lunchtime calories, compared to 900 among girls. Girls consumed the most calories during early- to mid-puberty (between the ages of 10 and 13), as they tend to have their most significant growth spurts during that time. Girls consumed an average of 1,300 lunchtime calories.
A study of teenage girls between 16 and 17, where 204 were dieters, and 226 were not, showed that “the mean reported energy intake of the dieters was 1604 kcals/day compared to 2460 kcals/day amongst non-dieters”, and that “more than twice as many dieters as non-dieters failed to achieve the reference nutrient intake (RNI) for retinol equivalents, thiamin, riboflavin, folates, vitamin B12, vitamin B6, zinc, copper and selenium,” which is obviously not healthy at all and suggests that consuming a low intake results in not being able to get enough of what the body needs, both in energy and in nutrients, because the body requires a much higher level of both. There was a similar study conducted on teenage boys.
Now you might say: yes but these studies show that on average unrestricted eating then leads women to need around 2500 calories on average and men to need 3000. Well, yes, those over 25, whose bodies have stopped growing and developing and so no longer need so much energy, do. But those below 25 still need 3000 and 3500 respectively, as their bodies need additional energy to grow and develop. Do remember here that the two studies above on teenage boys and girls are again, self-reported studies where the unrestricted eaters ate 2460 (females) and 3064 (males) – and as Gwyneth Olwyn points out, under-reporting can range from 2% to 58%, and that “if we average the studies reviewed by JR Hebert and his colleagues, then people eat on average 25% more than they think they do (or report that they do).” Also keep i mind that normal, healthy, energy-balanced people do not know the accurate calories in foods, which is why under-reporting can occur in healthy people, and the healthy intake can then be reported as lower than it is because they are going by what they perceive to be a healthy amount, which is constructed by our society in the form of the daily recommended allowance.
And there we have come full circle.
These intakes (2500 for women under 25, 3000 for women under 25 and men over 25, and 3500 for men under 25) are guidelines but best seen as absolutes during the recovery process due to the nature of the eating disorder and the way it will use grey areas to eat less than needed. If your own individual body requires, as a 30 year old woman, 2300 calories, then a extra few hundred calories will not mean that you gain a significant amount of weight more, if any at all, due to the fact that our bodies are able to get rid of energy by burning it off when it is not an excessive amount more than it needs (which would only be consumed by force feeding when you had reliable hunger cues – this does not include making yourself eat when you have unreliable hunger cues), and when you did eat intuitively when fully recovered, any excess weight would be lost again. Any small increase in weight past set point for a small period of time would be far more desirable than under-eating and remaining both physically and mentally ill.
As a p.s. I just want to put a study in about pregnant women and their energy requirements, as this is sometimes a question I receive on my blog. It reports that “in the normal-BMI group, energy requirements increased negligibly in the first trimester, by 350 kcal/d in the second trimester, and by 500 kcal/d in the third trimester.”
I would also like to refer you to Wikipedia’s list of how many calories on average people consume in each country.