Dr Oz had a guest on his show that aired on August 21st, 2014, just a couple of days ago, that helped to solidify my view that the Dr Oz Show does not care about evidence and is truly in the business of entertainment.
If I didn’t know about the Dr Oz show and was watching this show for the first time I would have thought it was some type of parody. But, regrettably, this was not a parody but a real “expert”, Josh Axe DC, saying all kinds of nonsense about human metabolism.
According to Josh Axe DC, there are certain foods, many considered healthy, which are really “Metabolism Death Foods” and are “shutting down our metabolisms”. He covers three of them on the show, see HERE. On the Dr Oz site he lists 5 foods, see HERE, and on his personal blog he expands the list to six, see HERE. I will focus on the three he discusses on the show but before doing that just a couple of quick points.
First, to be clear, most every thing Josh Axe said on the show was utter nonsense. I am stating this because there is a potential negative effect to pointing out nonsense, sometimes referred to as the “backfire effect” (Cook and Lewandowsky). Basically, by discussing the nonsense you can increase the awareness of the false information and it can lead to strengthening the view that is true rather than false. One method to help reduce this effect is to first point out very clearly that you are highlighting nonsense, which is why I am starting off with this.
Second, NONE of the foods he mentions have been shown to reduce a person’s metabolism. To clarify, I have yet to see any quality evidence that eating whole grains, peanut butter, or canola oil will cause a reduction in persons Basal Metabolic Rate (BMR), or how many calories a person will burn during exercise, or how many calories a person will use for the day, referred to as Total Energy Expenditure. This all means that these foods do NOT reduce one’s metabolism. Lets briefly review the 3 “Metabolism Death Foods”.
Josh Axe states that the following foods are “toxins” to the body, the body responds to eating these foods with a “fight or flight” (stress) response and they cause a “shutting down of our metabolisms”. Bullshit, oops, that one slipped.
He states that whole grains are “empty calories” and contain phytic acid which binds minerals, reducing mineral absorption and gluten “has been proven time and time again to slow down your metabolism”
His recommendations, use sprouted grain breads and coconut flour.
Okay, will start with a positive. Sprouted grain breads and coconut flour are great foods. That’s it for the nice stuff.
There is NO evidence that eating whole grains will reduce a persons metabolic rate. Yes, there is phytic acid in whole grains and yes they can and often do reduce the absorption of certain minerals (this deserves it own discussion), but that does NOT mean they cause a reduction in metabolic rate.
Whole grains are “empty calories”, that is just silly talk. I am sure the Paleo crowd went wild with that one and found a certain amount of warmth enter their nether regions. I do think that whole grains are NOT the holy grail of nutrition which they are generally thought of and humans CAN be very healthy without eating them. But, they do contain a number of valuable nutrients in them that are utilized and many cultures, for centuries, have been able to maintain a high level of health and stay lean regularly eating them (Fardet; Frolich et al). (I think there are some good arguments that a diet based on whole grains, such as the USDA 6-8 servings a day, is not a great diet for a fair amount of people, but that is for another day (Haywood, C & Proietto, J; Lindberg)) (1). Additionally, numerous weight loss studies, such as Mediterranean style diets, have utilized whole grains in the diets and the people who maintained a hypocaloric state (i.e., ate less than they burned) all lost weight (Esposito et al; Shai et al).
Josh also brings up the big boogeyman “gluten”. He states “gluten has been proven time and time again to slow down your metabolism”. There is currently a lot of misplaced concern over gluten and Josh is contributing to this problem (Brouns et al). There is no quality evidence that eating grains with gluten (wheat is top of the chart as well as rye and barley) causes a persons metabolic rate to slow down. Also, the recommended sprouted breads will still HAVE gluten in them as sprouting does not remove this protein. Sprouting will reduce the amount of phytic acid (Schlemmer et al). But phytic acid content has nothing to do with whether the food will cause a decrease in a persons metabolic rate.
The idea that eating whole grains will reduces a person’s metabolic rate is just wrong.
The next food that is recommended to avoid is;
2- Peanut Butter
Josh states “peanut butter is linked to slowing down your metabolism” and states that is mostly due to the aflatoxin, a fungus, that it contains and its potential negative effects on the gut bacteria.
The truth: There is NO evidence that peanut butter will reduce a person’s metabolic rate, i.e, BMR or TEE (see above).
Josh recommends that people switch from the evil peanut butter to almond butter, which Josh states “will absolutely rev up your metabolism”. Why you might ask? Well Dr Oz did ask, stating ” How does it speed up your metabolism?”, please do tell. Josh goes on to say that almond butter contains L-arginine which causes an increase in growth hormone which increases lean muscle. He states just one tablespoon of almond butter will “set your metabolism on fire”. At this point my neck was getting tired from shaking it back and forth, I think I may have developed a tick. But back to the nonsense.
Yes almond butter contains L-arginine, about 302 mg per 1 tbs, but, interestingly, peanut butter contains about 435 mg of L-arginine per 1 tbs, that is interesting (NutritionData). But this is really beside the point. The fact is, a single tablespoon or a whole jar of almond butter is NOT going to put on an ounce of “lean muscle” (I will take redundancy for $200 Alex). With that said, lets say, just for fun, it did increase, all by itself, no need to do that exercise stuff, “lean muscle”. How much of an increase? The evidence is overwhelming that while losing weight, which means people have to be in a calorie deficit, most people would be lucky to gain a few pounds of muscle which would lead to a whopping increase in daily metabolism of 30 calories, based on the fact that each pound of muscle increases metabolism by about 10 calories a day(please see this post, scroll to the bottom for my review of The 12 Second Sequence by Jorge Cruise for more details on this subject and references). The following is a slide from a lecture I did earlier this year which also summarizes this topic.
Back to the almond butter. One tablespoon of almond has about 101 calories which is over 3 times as many calories as the amount of additional calories burned by an increase in three pounds of muscle. That somehow eating a tablespoon of almond butter will, in any real way, lead to an increase in muscle tissue is just absurd! Also, his beloved almond butter, which I do think is a good food, contains a good amount of phytic acid, the stuff he was concerned about with whole grains. In fact, almonds have the highest amount of any nut, including peanuts, and likely have higher levels than whole grains (Schlemmer et al).
One final aspect regarding peanuts, which Mr Axe brought up, was aflatoxin, which I will just briefly touch upon here.
Aflatoxin is a toxin produced by certain molds/fungi, which is considered a carcinogen, particularly liver cancer (see HERE). Yes, peanuts are one of about a dozen foods that can and often do contain some level of this fungus. Of the other foods that can contain aflatoxin, most pertinent to the current discussion, is ALMONDS (Rodrigues, P. et al; and HERE). Overall, on a health perspective, it is best not to eat lots of peanuts or other foods that can be contaminated with aflatoxin and to visually inspect foods for this fungus (see HERE, HERE). But, this has nothing to do with a person’s metabolism or their ability to lose weight.
Can you see how what he is saying is just so ridiculous. But lets continue with highlighting the nonsense.
The third and final “Metabolism Death Food” is;
3- Canola Oil
Josh states that canola oil “is a partially hydrogenated oil” and it “causes inflammation throughout the body”
I really thought I didn’t hear him correctly, so I listened to this statement a few times. Nope, he really said this. I was very surprised to hear canola oil referred to as a “partially hydrogenated oil”. So I checked into it, hello PubMed and Google. I went into this search thinking this was not true at all, but something cool happened….I learned something and have to admit I was wrong, but only kind off. But, before I possibly bore you with some interesting details on the topic, I will give you the punch line with respect to the metabolism aspect. Canola oil does NOT slow down someones metabolism !! (Lin et al). Ok, back to the details about canola oil.
I am not sure why Josh states that canola oil is “a partially-hydrogenated oil”. From what I can tell canola oil is only partially-hydrogenated for certain applications (i.e., deep fryer oil) and the canola oil that is used in salad dressings and the stuff you by off-the-shelf for cooking (such as the bottle that was displayed on the show) is NOT partially-hydrogenated. If an oil is partially-hydrogenated it has to state it on the label. So from what I can tell his statement is very misleading and not true for most canola oils.
But, as stated above, I did learn something while I was reviewing the research on this topic. It does seem true that canola oil, as well as soybean oil, the common types used for salad dressings and cooking, do contain a small amount of trans fats, which can range from 0.56% to 4.2% of its fats (O’keefe, S. et al). It does look like this can be lower when it is cold-pressed or expeller-pressed. Yes, trans fats are not good for health, but, the evidence (see below) that ingesting small amounts of canola oil leads to increased inflammation or poor health is not currently supported.
The evidence to date does not support the idea that ingesting canola oil increases inflammation (Lin et al) (2). Overall, as shown in the figure below, I think canola oil has a rather neutral effect, and can be included, (relatively small amounts, say 1-3 tablespoons a day) in a weight loss as well as a health promoting diet.
His recommendation is to replace canola oils with Grass Feed Butter. There is nothing wrong with grass fed butter, and butter in general, and it can certainly be part of a weight loss and health promoting diet. He recommends this item mostly for its CLA (conjugated linoleic acid) content because “35 studies show that it burns belly fat”. The fact is, the evidence for CLA showing that it helps with fat lass, and “belly fat” in particular, is very weak. I reviewed this topic in-depth about 3 years ago and found the real world benefits to be very small if any, see HERE (Thiboutot). Additionally, the folks over at Examine.com have extensively reviewed the research and concluded;
“A pretty poor fat burner, and even more unreliable than it is bad at burning fat. It might make you lose enough fat to compensate for that cookie you had once.
It has no astounding other affects on health or anything, it just seems to be quite an overhyped and uneventful molecule(s)” (Kurtis Frank, Examine.com)
The other important aspect is HOW MUCH is needed to even produce any benefit? The range of CLA intake to even have a “fat burning” effect is 3,200 to 6,400 mg a day (Examine.com). This brings us to the amount of CLA in grass fed butter. The evidence is clear that grass fed butter does have much higher amounts of conjugated linoleic acid (CLA) than butter from grain fed cows (Dhiman et al). Grass (pasture) feed cows seem to produce a maximum of 22.1 mg per gram (Dhiman et al). Therefore, ONE tablespoon of butter (14 grams) would have about 309 mg of CLA along with 100 calories. The 309 mg is nowhere near the 3,200 to 6,400 mg that has been studied and shown to have a possibly positive effect. To even get to the lower end (3,200 mg) you would have to ingest about 10 tablespoons of grass fed butter which brings with it 1,000 calories. There is just NO evidence that a tablespoon or two of grass-fed butter will have any “fat-burning” or “metabolism boosting” effects.
Josh Axe is uttering nonsense and is causing more confusion about what really matters for losing weight and maintaining a healthy weight. The Dr OZ Show and Dr OZ himself are also big contributors to the confusion by airing this crap on the show. Finally, if you read his articles on the Dr Oz site or on his own site you will see that Mr Axe has NO references listed. Yes, a couple of times he alludes to this or that study or in the case of CLA “35 studies” but never actually gives the proper citation. So besides spouting nonsense, he doesn’t take the extra step, which is part of writing a non-fiction piece (maybe he is actually writing a fiction piece?), to clearly display his sources. Could it be that there isn’t any quality evidence to support his statements? As I have shown above, this is very likely the case, but I am certainly open to rebuttals that can show that there is some quality evidence for what he said.
(1) – The whole grains and health thing is another big topic that I am not covering in detail here but did want to mention that the bulk of the evidence for benefits comes from epidemiological evidence and, when considering the hierarchy of evidence, is generally on the low end. However, I don’t think there is any good evidence that including some whole grains in the diet has contributed to the increase in body weights that have occurred over the past 40 years and they do not inhibit the ability to lose weight.
(2) – The Lin et al paper was supported by by the Canola Council of Canada and the U.S. Canola Association and a few authors work for these agencies. This is a red flag, but it does not automatically mean the information presented is false or misleading. It was peer-reviewed (yes, I know that’s not perfect) and I did read it and found that the research on the topic was well covered and, as stated above, the general conclusion is that canola oil has a rather neutral effect on health with some potential benefits and ingesting relatively small amounts of this oil is not harmful.
Amino acid content retrieved from http://nutritiondata.self.com/
Brouns, F. et al (2013). Does wheat make us fat and sick? J Cereal Science; 58: 209-215.
CLA retrieved from http://examine.com/supplements/Conjugated+Linoleic+Acid/
Cook, J. & Lewandowsky, S. (2012). The Debunking Handbook. St. Lucia, Australia: University of Queensland. November 5. ISBN 978-0-646-56812-6. Retrieved from http://www.skepticalscience.com/Debunking-Handbook-now-freely-available-download.html
Dhiman, T.R. et al (1999). Conjugated linoleic acid content of milk from cows fed different diets, J Dairy Science; 82: 2146-2156.
Esposito, K. et al (2011). Mediterranean diet and weight loss: meta-analysis of randomized controlled trials. Metab Syndr Relat Disord; 9(1):1-12.
Examine.com (n.d.). Conjugated Linoleic Acid. Retrieved from http://examine.com/supplements/Conjugated+Linoleic+Acid/
Fardet, A. (2010). New hypothesis for the health-protective mechanisms of whole-grain cereals: what is beyond fibre? Nutrition Research Reviews; 23: 65-134.
Haywood, C & Proietto, J. (2012). Wholegrains: Emerging Concepts, Controversies and Alternatives. Food and Nutrition Sciences; 3: 1156-1161
Lin, L. et al (2013). Evidence of health benefits of canola oil. Nutrition Reviews; 71(6): 370-385.
Lindberg, S. (2010). Food and western disease. Health and nutrition from an evolutionary persepctive. Wiley-Blackwell, United Kingdom.
O’keefe, S. et al (1994). LEVELS OF TRANS GEOMETRICAL ISOMERS OF ESSENTIAL FATTY ACIDS IN SOME UNHYDROGENATED U. S. VEGETABLE OILS. J Food Lipids; 1 (3): 165-176.
Rodrigues, P. et al (2012). Aflatoxigenic Fungi and Aflatoxins in Portuguese Almonds. The Scientific World Journal; Article ID 471926,
Schlemmer, U. et al (2009). Phytate in foods and significance in humans: Food sources, intake, processing, bioavailability, protective role and analysis. Mol Nutr Food Res; 53: S330-S375.
Shai, I. et al (2008). Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet. N Engl J Med; 359 (3): 229-241.
Thiboutot, J. (n.d). CLA & Weight Management: Will it help?. Retrieved from http://doingspeed.com/cla-reason-report/