Scientists Discover Drinking Milkshakes for Breakfast is Bad For You

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Heads up, if you have an eating disorder you may want to give this video a skip! I’ll be talking about diets.

What you put in your body matters. Eating too many calories makes you fatter, and eating too few makes you thinner, but more than that eating a lot of protein can build your muscles, carbs can give you energy, fats help you absorb nutrients. Too much of some things, like sugar, can royally fuck you up, which scientists are starting to dig into more, which really pisses off the Big Sugar lobby. I’ve talked about this before, like last year when I pointed out studies suggesting that eating ultra-processed food might make you eat more and feel like shit.

However, there are a lot of claims of what bad diets can do to you that aren’t really well-founded. So let’s start out with the takeaway from this video: there is no solid evidence that eating a Western diet can fuck up your memory. However, a new study now claims that, in fact, eating a Western diet can fuck up your memory, which I saw over on good old Yahoo! Sports. It’s ironic because I, a Westerner, had forgotten Yahoo! existed. I suppose my diet is to blame.

This was an Australian study in which they had 55 students eat a “Western-style” diet. I can already feel some of you getting annoyed — like, what the fuck is a Western-style diet? There’s no way people in the US eat the same as people in, say, France or Greece. And it’s true — it’s a bad name for what is, actually, a fair stereotype of what people in the United States eat and what we influence many other cultures to eat as well through the proliferation of KFCs and McDonald’s around the world. 

So to emulate a “Western diet” they had their subjects eat something horrible each day for 8 days. On the first and last days, that was a breakfast of a toasted sandwich and…a milkshake. Yes, a milkshake. For breakfast. “But I don’t eat milkshakes for breakfast,” you cry with your Western tears. Oh, don’t you? Because a 16 ounce milkshake from Whattaburger is 420 calories (lol) but a 16-ounce iced white chocolate mocha is ALSO 420 calories but with way more fat. And don’t even get me started on the Caramel Ribbon Crunch Frappuccino® Blended Beverage. Face it: maybe you don’t, but a whole lot of Americans drink milkshakes for breakfast.

For days 2-7, subjects had to eat TWO ENTIRE BELGIAN WAFFLES on four of the days and on the rest of the days they had to buy something at a fast food restaurant consisting of a main meal plus a drink or dessert.

For the rest of their meals, they were instructed to eat as they usually do. A control group was asked to eat the Day 1 & 8 sandwich/milkshake breakfast (though one with fewer calories, fat, and sugar) but then just eat like normal the rest of the week.

Researchers gave the subjects memory tests before and after their diet changes. They also asked them how much they liked the food they were eating and whether or not they wanted more. 

Here’s why: their hypothesis is that the western diet damages the hippocampus. This region of your brain is responsible for appetite control, and also for memory. I reported before about how people eat more when they eat ultra-processed food, even if they didn’t like the taste of the food that much. Well, maybe this is because these foods damage the hippocampus, making it so that even though you’re full you still want more of a food regardless of how much you actually liked eating it. We can test that by seeing if people eating this diet also have memory problems, since that is also done by the hippocampus.

This study found that yes, the people on the western diet were more likely to screw up their memory test and more likely to want more food regardless of how much they like it.

So, what’s the issue? Well, there are a few: for a start, this group experienced a drastic change of diet. They came into the study with a healthy BMI of about 22, and then began eating an estimated daily calorie intake of 2,420 calories (or 10,127.4 kilojoules). That is an absolutely insane amount of calories to eat every day for a week when you have a BMI of 22. According to the stats given for the average participant, they were probably eating a max of 2,000 calories a day prior to the study, being mostly women (who are an average of 5’3 in Australia) with a BMI of 22 with moderate to active exercise.

That’s a huge change, and this study doesn’t tell us if people fuck up on memory tests when you drastically change their diet for a week. The control group stayed on their usual diet, but there’s no third group that suddenly dropped 420 calories a day, or ate an extra 420 calories of lean fish or vegetables.

So maybe it was the calories, or maybe it was the higher fat. Or the higher sugar. Or a combination of higher fat and higher sugar. Again, this study doesn’t tell us that. That doesn’t mean it’s a bad study, it just means that there’s a lot of additional work to be done.

Finally, I want to note that there may be a little p-hacking here. The test the western diet group failed was a verbal word memory test. They also took a test on logical memory and there was no difference between the groups. If you look at several possible outcomes but only find one, that means that follow-up tests need to just look at that one outcome so you can drill down and see if it was just a statistical blip — especially when you only have 55 people in each group, and especially when it’s based on only one week of diet change.

So no, don’t panic about your shitty diet screwing up your memory. Feel free to continue to worry about how your shitty diet is screwing up the entire rest of your life, like when I eat too much and put on weight and then my back goes out and then for the next year I can’t stand up for longer than 5 minutes at a time. The human body is fun! Wait…what was I talking about?

Rebecca Watson

Rebecca is a writer, speaker, YouTube personality, and unrepentant science nerd. In addition to founding and continuing to run Skepchick, she hosts Quiz-o-Tron, a monthly science-themed quiz show and podcast that pits comedians against nerds. There is an asteroid named in her honor. Twitter @rebeccawatson Mastodon mstdn.social/@rebeccawatson Instagram @actuallyrebeccawatson TikTok @actuallyrebeccawatson YouTube @rebeccawatson BlueSky @rebeccawatson.bsky.social

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One Comment

  1. It seems to me they really wanted to forget that horrible diet they were forced to consume, and, perhaps, some other things got lost in the purge.

    I have another hypothesis:
    Doing small, poorly controlled studies causes the researcher to forget that correlation does not equal causation.

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