SS 209 – Does Diet Soda Make You Fat?

Episode 209 Show Notes

Grant and Heavey dive into the correlation between diet soda and weight gain. Do artificial sweeteners really make you fat? If so, is it something you should eliminate from your diet? The result may surprise a lot of people! Listen in to find out.

[03:10] The Reddit Gifts

Grant recently started using Reddit and signed up for Reddit Gifts, which is a yearly Christmas program, where you register your name and address. They open it up to people around the world and they randomly match you with another Redditor who also signed up for it. So you’re pretty much paired up with a stranger.

In the first year, you exchange gifts with people within your own country. But once you’ve proven your merit as a Secret Santa and given quality gifts, you can be elevated to a better version where the exchange of gifts happens around the world. Grant says that what’s even better is being able to reach out to people who are harder to get to.

Grant just found out that he matched with an 18-year-old kid from a rural community in Washington.


[06:00] Don’t Get the Ice!

Heavey has an upcoming trip to Mexico. He came across something on Reddit about the best secrets to know relating to a number of industries. One of them was from a flight attendant that said, “Don’t get ice in your drink. Don’t drink coffee with your hot water on the plane. And don’t touch anything in the lavatory with your bare skin.”

Basically, the ice is put into trays and the trays don’t get cleaned very often at all. Also, flight attendants touch every surface on the plane as they go up and down the aisle. You’re lucky if you get off a plane and don’t get sick.


[09:30] Artificial Sweeteners in Diet Soda

There’s a crazy perception around artificial sweeteners. Some people eat all sorts of junk food but won’t come close to touching anything that has artificial sweetener. A lot of people believe artificial sweeteners might cause health issues. This could be based on the original research that has been discussed in the past episode touching on this topic, where they found a connection between artificial sweeteners and cancer. However, that was in rats that had different mechanisms and with extremely high doses of artificial sweetener. Hence, those weren’t really relevant. All that being said, how is diet soda related to weight loss?


[12:13] Diet Soda and Weight Gain


A few years ago, there were headlines about how diet soda was related to weight gain. So how true is this? A lot of people are implying that even though we don’t understand the mechanisms behind how sweeteners can actually interfere with metabolism. This has put people off from consuming them. However, there’s not much research to support that so it’s purely speculation at this point.

Nevertheless, observational research has been done where they correlated obese people consuming diet soda. There is user bias that comes with this since overweight people obviously want to consume diet soda because they want to lose weight. So it makes sense that more overweight people are consuming diet soda. Heavey suggests that there’s really no strong evidence that artificial sweeteners stimulates appetite in humans. However, he did just find a new study, which is a controlled trial that he came across recently.


[14:30] A Controlled Study on Artificial Sweeteners vs Water

This nine-week study looked specifically at whether or not artificial sweeteners affect intake and feelings of hunger and sweet cravings. The researchers compared artificially sweetened beverages with water at mealtime. They used the same type of sweetener which was actually a combination of two different sweeteners. The participants of the study are 150 healthy men and women who are non-habitual consumers of artificial sweeteners.

Conducted in France, they measured subjective gradients of hunger. They also occasionally brought them in and had them eat in a buffet style meal to measure the total intake among the participants.


[15:53] Is There Bias Involved Here?

This study was sponsored by Coca-Cola. Some people might have this notion that just because industry funds it, that we should dismiss it out of hand, But Heavey does not conform to that. Why? Because oftentimes, that’s the only way this kind of research can be conducted.

Additionally, Grant puts out there that if they were to find out that artificial sweeteners make people gain weight, people are either going to avoid those drinks and drink more water. Or, a worst case scenario is they’re going to figure out where to put their marketing dollars and which products they’re going to promote in which way. So it’s actually for their benefit to know these things.

Moreso, the researchers disclosed the financial relationship in this study up front, which is a plus. Alternatively, this gives us all the more reason to be on high alert. Hence, we have to look at it with more scrutiny than we otherwise would have.
[17:23] Some Red Flags… Hmmm…

One red flag though is that the authors took the very positive step of pre-registering their study. For instance, they announce in advance that they’re studying xyz and looking at Diet Soda and they’re going to look at measures of hunger as their primary outcome and they’re going to measure before and after this point of the study. Basically, they inform everything they’re going to do in advance so they can’t get a negative finding and look for something else they want.

However, they’ve changed their primary outcome between the manuscript and the publication and this is not a great sign. It means they said they’re going to look at one thing as their main outcome. But then when they published it, they didn’t look at it in the way they originally outlined it.

For example, when they looked at the appetite ratings, they said they’re going to look at it at one point of the study. One point could be that they could be coming in at baseline and there’s some that don’t have any sweetener. Then you go on to sweeteners for a couple of weeks and then you come off of them. In short, there were a lot of manipulations involved that were too complex. As to why they did that, we don’t really know. Whether it was to make their results look more positive, one can only assume. Plus, they didn’t publish all their data.


[19:44] What They Found

The study found that there were no significant differences in gradients of appetite, desire for sweets, caloric intake, or macro ratios. So whether you drink diet soda with artificial sweeteners or water at mealtime, there’s no difference.

Additionally, the authors defined the “difference” by being 15% or more intake, which is a significant margin. A 10% difference in intake could lead to weight gain over the long term.

But while they found no difference in the intake, Heavey noticed that the female group was actually 14.7% higher for the sweetener group. And so it seems it might have been intentionally selected for 15%.

So does this mean that drinking diet soda makes you want to eat more?

[21:55] Major Takeaways

Heavey describes the study as being too short to give us any long-term information. But there are some important points that people can take away from the way the research was conducted. Heavey actually dug into a wider research from a wider literature search and uncovered a meta-analysis where no significant change was detected for artificial sweeteners as opposed to water.

He also found another study that replaced regular food and beverages with artificial sweetening versions that led to some weight loss.

Additionally, Heavey looked at the hormonal piece and the study looked specifically at appetite-regulating hormones. And they found no significant difference between artificial sweeteners and water.

[25:30] Coca-Cola Sells Alcohol Now (in Japan)

In May 2019, Coca-Cola released their first alcoholic beverage called Lemon-Do, with 3-8% alcohol.

Ultimately, there’s no strong conclusion on artificial sweeteners and so there’s no real reason to be scared of it.

LInks:

Reddit Gifts