Why We Underestimate What We Eat

Studies show again and again that we humans have a great tendency to underestimate what we have eaten during the day. We even like to play down the probable calories we are eating in our foods, especially when it comes to snacking.

Is this just human nature, are we lying through our teeth to save face, or are we in denial?

Turns out we can blame our diet.

While it may seem refreshing to actually have something to blame other than ourselves, we are still left with what to do about it.

But let’s back up for a second, because there is some interesting stuff here.

Many Ways to Forget

One of the standard strategies to use when people start a diet is to ask them to fill out a food diary which includes everything they eat over a period of a week or a few days. While this can be a good way to increase awareness of food consumed, many people consciously or unconsciously “fudge” their actual intake.

Why? When asked about this, some people will admit to feeling embarrassed or guilty. (e.g., “I only ate a few chips.”) Others say recording food intake is simply too much effort, especially if it requires weighing and measuring foods. Still others have difficulty knowing what a standard serving size is.

There is a lot of research that relies on individual’s memory or recall of what they ate. Amazingly, some studies even ask people about their specific tendencies over months or even a year! And here’s the thing. A study at Cornell University (and many others I would guess) found that everybody underestimates! They found that normal weight people underestimate calorie intake by about 20%, and overweight people underestimate by about 40%. Other sources say it’s more like 50%.

So at least you can rest easy knowing that you are not alone.

What About Our Diets?

Just how does our diet mess with our ability to be honest about what we are eating?

Disclaimer: Consequences of WHAT we eat and how it affects our perceptions of HOW MUCH we eat are going to vary greatly, depending on many factors. For the purposes of this blog, I am going to home in on just a few things can greatly affect how we eat.

The few things are: (1) Our “Western Diet”, and (2) our brain, specifically the place that is responsible for learning , MEMORY, and cognition, the hippocampus.

First of all, let’s describe the Western Diet. It’s characterized by high intake of saturated fat and refined carbohydrates (remember those chips from before?) and frequent consumption of processed foods. Processed foods are manufactured to be high in sugar, fat, and salt and to be highly palatable and rewarding. Unfortunately, it is now estimated that 50% of the calories consumed by Americans are now from processed items. Statistics also indicate that only 15% of Americans are consuming the recommended minimum of 5 servings of fruits or vegetables daily.

If you are not eating this way, great! You can stop reading now (kidding).

Now for the Naked Truth

The Western Diet effects our brains, and our memory. Here’s where the hippocampus comes in. It can become dysfunctional on the Western Diet. Before you start thinking it’s just about forgetting about a few foods consumed, read on. What happens when the hippocampus becomes compromised is a laundry list of bad things.

Here they are (sorry, but we will get to the good part later). Effects include (1) an increase in food intake, (2) increase in body weight, (3) heightened response to food cues (and cravings), (4) impaired attention to internal cues regarding satiety, and (5) reduced ability to inhibit food intake.

And, here’s the kicker: hippocampus dysfunction can dampen our ability to anticipate the consequences of eating. Taking this a step further, a person may not be able to use past experiences to remember that eating past satiety will not be rewarding.

The Good Part (some solutions)

Instead of judging people (or ourselves) for all of the above, we can go back to blaming our diet and do several things:

The most powerful solution would of course be to switch from the typical Western Diet to a style of eating that embraces whole, unprocessed foods. Aside: I know this can be a tough sell. Many people feel that the Western Diet is “normal”, and do not feel that “healthy” foods taste very good. But we have to try.
We can teach mindfulness to help people pay more attention to sensations, memories, thought patterns, and emotions related to what they are eating. This can be a way to take away distractions so there is more focus on actual intake, giving an individual the time and space to consider the negative consequences of a food choice or portion.
Disseminating basic information about what happens to our brains and bodies on the Western Diet. Awareness of the barriers to weight loss brought on by the Western Diet (and our resultant faulty memory processes) may help individuals develop objectivity and more enlightened strategies in the quest for weight loss and healthier eating.

All the best
Kristen

There is a more in-depth version of this article published in Psychology Today blogs, 7/20/21, under the same title.