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Student Questions: Bitters, Gas, and Diet Woo

Skeptoid answers another round of questions sent in by students all around the world.  

by Brian Dunning

Filed under Feedback & Questions

Skeptoid Podcast #578
July 4, 2017
Podcast transcript | Download | Subscribe



Once again we head to the virtual mailbox of student questions, sent in by students of any age from any institution anywhere in the known universe — maybe some of them have even come from an unknown universe, how would I know. Anyway, I do my best to give each the full Skeptoid treatment. Today's questions cover alcoholic bitters, gasoline additives, pandas, and the usual assortment of fad diet woo.

Let's get started with a subject most students probably shouldn't know to ask yet:

Hi Brian, my name is Aaron and I'm enjoying one of my favorite cocktails, an Old Fashioned. Curiosity led me to Google bitters which is one of the ingredients, and I found some claims I'd like to know more about. One source claims that bitters "balances one's appetite" and "curbs sugar cravings", while another source claims that bitters stimulates appetite and are used to encourage weight gain. These come along with plenty of other health claims. Is bitters a health food?

This is a subject rife with pseudoscience. As you know from your Google search, this will take you to all kinds of alternative wellness sites. Most of the claims I found say that bitters aids in digestion, or helps you digest your food more completely. I found a grand total of zero scholarly articles discussing research on this. In my experience, a lack of published research usually means that a claim is particularly vague — too vague to test — or simply not supported by any consistent observations.

Bitters is made similar to absinthe (discussed in detail in episode #515), a preparation of water and alcohol in which some collection of botanicals has been steeped. Its history is also very similar; it was originally sold as a patent medicine, in all its many varieties. Just about any botanical you can think of can be added to bitters, and has been at some point; and some salesman has probably sold it as a cure for anything you care to name. At its height in the late 1800s, bitters was widely consumed — nominally for its medical value, but actually for recreation.

Also like absinthe, alcoholic bitters was banned in Prohibition, which only added to its legend. We now know that there are no real medical benefits to any of these drinks, only the lasting belief that they harbored some sort of secret herbal cure-all. In short, no, bitters is not a health food.

Hi, my name is Andrew from Oregon, and I'd like to know what you think about gasoline additives, such as fuel injector cleaners or synthetic additives that gasoline companies advertise that they put in their gasoline to make your car run better or remove buildup from the inside of your engine. Thanks a lot.

In the United States, most gasoline companies participate in a voluntary standards system (established by automobile manufacturers in 2004) called Top Tier, which requires their fuel meet rigorous standards for controlling deposits in the fuel system, much tougher than the minimum standards established in 1996 by the Environmental Protection Agency. Deposits in the fuel system reduce efficiency, causing your engine to make less power and produce more emissions.

AAA, the American Automobile Association, recently published the results of a major research project in which they compared the results of using Top Tier and non-Top Tier fuel. They found the difference was remarkable, much greater than they expected. Non-Top Tier fuel created 19 times as much deposits than did the good stuff.

The cleaners that you can buy separately as an additive should work just as well; however, they are not price competitive with simply buying Top Tier gas. Adding such a product to gas that's already Top Tier usually does not add any benefit, and may actually reduce performance.

How do you know if your favorite gas station sells Top Tier gas? If it's a major brand, it probably does; but you can check for sure at Use Top Tier gas, use the right octane grade specified by your car's manufacturer (neither higher nor lower), and you're treating your engine as well as you can.

Hi Brian, my name's Cale and I live in the state of Oregon. I recently heard about something called the Shangri-La diet, wherein a person consumes a few tablespoons of oil a day in order to suppress appetite and to manipulate something called the set point which is a hypothesized natural homeostasis for the body's weight. What's your take on this weight loss approach?

Obviously you're right to be skeptical of this or any other fad diet. This is yet another miraculously easy solution to a difficult problem: continue eating whatever you want, but also sip a small amount of olive oil each day; and your body will automagically "want" to be skinnier, and the rest takes care of itself. Needless to say, no controlled trials have ever been published on this, no data supports it, and there's no sound theory behind it. It's popular because its non-expert creator wrote a book which publisher Penguin successfully got showcased on Good Morning America, upon which it shot to the bestseller list. As we see so often, people believe whatever publicists want them to believe.

The idea of a "set point" is undefined and a bit controversial, but reasonable. It's the approximate weight everyone naturally returns to after stopping a diet, or recovering from pregnancy, or any other weight change. This does tend to happen, probably due to many complex physiological processes; but there's no sound theory supporting the idea that there is a single "set point" number that can be easily dialed up or down, and your body will follow suit. That's pure pseudoscience, and it's the core of this claimed magically easy solution.

It follows that there is also no theory supporting the idea that drinking olive oil, or anything else, will turn this dial up or down, and certainly no evidence.

Hi Brian, this is Gary. I'm at a university in Singapore. My question is about glycemic index, and whether I should be using it for planning my diet. The glycemic index first came out it made intuitive sense, but I was told that it was controversial because some findings contradicted established science for complex versus simple carbs, plus there were also unexplained variations across people for the same food, and within the same person at different points in the day. I'm wondering what's the latest story on glycemic index. Should I be using it to plan my diet? Thank you.

The glycemic index is a measure of how quickly a certain food raises your blood sugar level, and it was developed as a tool for people with type 2 diabetes. When you have this, your body doesn't use its insulin properly and so can't manage spikes in blood sugar, which can be very dangerous. The glycemic index is intended to help diabetics avoid foods likely to impact their blood sugar.

You're right about its inconsistency. To determine a food's glycemic index, test subjects are given whatever amount of the food contains 50 grams of carbohydrate. Then their blood sugar levels are measured for two hours as it rises then falls back, and the glycemic index is determined. One obvious problem is that enough of a food to contain 50 grams of carbohydrate is going to be, in some foods, less than one might typically eat; and in others, far more than one could ever reasonably eat. So in many cases, foods with a high glycemic index can still be safely eaten, because a normal serving is way less than the amount needed to produce a spike in blood sugar. So it's not perfect, but it's still one tool for diabetics.

But as far as weight loss goes, no, there is neither empirical evidence nor sound theoretical foundation for eating a glycemic index diet for weight loss. It's like choosing a car with comfortable seats hoping to achieve good gas mileage. The two don't have anything to do with each other.

But yes, of course, you will still find plenty of promotion of the glycemic index diet for weight loss. Any effects it might have are probably just the effects of eating a restricted diet, which usually means less total food. But that won't stop people from selling books.

I'm Zach, a student from Oklahoma, and I have a question about the giant panda. When I was a kid, I was always told that it wasn't really a panda bear, because pandas were more related to raccoons than they were to bears. But I have read in more recent books that pandas are related to bears and are not related to raccoons. I've been looking on Google and I just keep finding conflicting answers. So I was wondering is there consensus among biologists about is the panda more related to the bear or the raccoon?

You are correct that for a long time, there was debate about how the panda should be classified in the taxonomy. The markings on a panda look like those on raccoons, and many aspects of the behavior and anatomy of pandas differ from bears. So although we always had it classified as a bear, there was always debate.

But in the 1980s, genetics had progressed far enough that we were able to prove for a certainty that the panda is indeed a bear, and if you look at today's taxonomy databases you'll find their classifications, correct to our current best knowledge. Pandas, other bears, and raccoons are all part of the Caniformia suborder (dog-like carnivores), and shared a common ancestor some 40 million years ago. From then on, they split apart: bears into the Ursidae family, and raccoons into the Procyonidae family, which also includes olingos and coatis.

One final note: Don't be fooled by the red panda, which is not a panda or a bear or a raccoon. It actually comes from yet another branch of the Caniformia suborder.

So students, keep these questions coming. (Sometimes you can cheat and also send one in if you're not actually a student, it's not like I check or anything.) If you're a teacher, you should make every student in your class send one in! All you do is record your question with the voice memo app on your smartphone and then email it to I'll try and answer it on an upcoming show. Thank you so much, students, and keep your skeptical eyes peeled!

By Brian Dunning

Please contact us with any corrections or feedback.


Cite this article:
Dunning, B. "Student Questions: Bitters, Gas, and Diet Woo." Skeptoid Podcast. Skeptoid Media, 4 Jul 2017. Web. 19 Sep 2017. <>


References & Further Reading

Binkowski, B. "Tall Tale Cocktail." Urban Legend Reference Pages., 14 Apr. 2016. Web. 30 Jun. 2017. <>

Editors. "Is Panda bear related to Raccoon?" ScienceLine. University of California Santa Barbara, 22 Sep. 2015. Web. 29 Jun. 2017. <>

Harris, R. "Role of set-point theory in regulation of body weight." Official Journal of the Federation of American Societies for Experimental Biology. 1 Dec. 1990, Volume 4, Number 15: 3310-3318.

Mayo Clinic Staff. "Glycemic index diet: What's behind the claims." Nutrition and Healthy Eating. Mayo Clinic, 27 Feb. 2015. Web. 29 Jun. 2017. <>

SAE Fuels & Lubricants Council. "Gasoline Detergent Additives: Are they worth the extra money at the pump?" Learn. SAE International, 16 Sep. 2013. Web. 29 Jun. 2017. <>

Stepp, E. "AAA: Not All Gasoline Created Equal." AAA Newsroom. American Automobile Association, 7 Jul. 2016. Web. 29 Jun. 2017. <>


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