I work at a university and I do human research. A very important part of doing human research is the informed consent process. Informed consent is based on the basic principle of respect for human beings and acknowledging that people have the right to information in order to make knowledgeable decisions about whether to participate and continue in a research study.

At my university, I also sit on one of the Institutional Review Board (IRB) Committees, which reviews proposals for new and ongoing human research studies. With each new research proposal we review a number of documents including, in most cases, a written informed consent form that describes the details of the study. A common critique of informed consent forms is that they include too much medical jargon. An example is, instead of telling people that you will draw “5 ml of blood,” tell them that the amount of blood to be drawn is “approximately 5 teaspoons.” The idea is that the average person has a better understanding of what a teaspoon is as compared to a milliliter because, at least in the United States, a teaspoon is a more familiar unit of measurement.

So, this got me thinking about how we use, measure, and try to track sugar in our diets. The amount of sugar in the foods we eat has become an increasing concern in the wake of the rising numbers of children and adults who are overweight and obese – and the amount of sugar in various foods is not always easy to conceptualize. For example, if someone asked you how much sugar was in something, odds are you would probably respond with a number in “grams.” Yet, the way we use sugar typically consists of a sprinkle on top of a dish, a spoonful into a coffee, or a cup or so into a recipe – most of us probably don’t use sugar in gram increments and probably don’t have a very good idea of what 5, 50, or 500 grams of sugar actually look like*. In addition to not having a very good idea of what a gram of sugar looks like, it’s easy to miss, forget, or ignore how much sugar is in some of the foods and beverages that we regularly encounter. Here are a few examples:

So, first off, it’s easy to miss the fact that a medium chocolate shake at McDonald’s has more sugar in it than 24 Oreo cookies! But that’s not all. Some scientists think that what really counts is how the sugar is absorbed into the bloodstream and what effect it has on your body. To measure the impact that sugar has on the body, scientists have come up with terms such as “glycemic index” and “glycemic load.” Glycemic index is a measure of how much and how quickly the sugar from a food will enter the bloodstream (roughly, how much it will increase blood sugar and insulin levels). Glycemic load takes into account both the rate at which sugar enters the blood stream and total quantity of sugar in that food. So, for example, watermelon has a high glycemic index because the sugar in watermelon gets right into the bloodstream (it’s just sugar and water after all). But there isn’t much total sugar in watermelon, so it’s glycemic load is relatively low. So, let’s look at the glycemic indices and glycemic loads of some of those same foods:

You can see that compared to the first table where the amount of sugar in a Snickers wasn’t too much more than that in an apple, taking the glycemic index of the Snickers into account results in a glycemic load that is three times that of an apple. In a similar manner, the first table shows that the amount of sugar in two cups of Cheerios (2 g) is quite a bit lower than that of an apple or orange (23 g). However, in the second table where the relatively high glycemic index of Cheerios is considered, the glycemic load of Cheerios is also about three times higher than that of an apple.

This brings me back to the issue of informed consent and the idea that respect for people is paramount. If I were conducting a research study of two new compounds called “McDonald’s milkshake” and “Snickers,” the IRB (and perhaps the FDA) would expect me to fully describe the risks and any potential benefits related to the administration of these compounds. It is possible that just stating that the shake contained 111g of sugar would not be good enough and that they would also ask me to describe the amount of sugar in a more familiar way. For example, by stating that you would have to eat 8 apples in one sitting to get the same amount of sugar as you get from one medium McDonald’s chocolate shake or that the glycemic load of a Snickers bar is three times that of an apple. Personally, I like the idea of “apple equivalents” as a unit of measurement.

The point here is not to make people think that a shake or a candy bar is dangerous or evil, but simply to inform the public in a way that is easy to understand. As consumers, we should have the same rights as research subjects to clearly understand what we’re getting with the products that are allowed to be marketed and sold to us.

So, the next time you look at a holiday dessert or candy bar, consider pausing for a moment and asking yourself, how many apples is that?

*If you have a scale handy, try this right now. Place a piece of tape or paper over the readout and measure out three amounts of sugar that you think are equal to 5, 50, and 500 grams. Then place them back on the scale with the tape removed and see how close you were to the actual amounts. How did you do? Bonus: weigh out the actual amounts. Do any of the amounts of sugar surprise you?

=============================