For anyone who hasn’t been keeping up with all the posts here at Burn the Fat Blog, the team at Examine.com wrote our “most liked’ post ever a few months ago, in which they talked about the actual science behind 10 popular fat burners. They did a great job taking complex science and making it accessible to you, and so for an encore, I asked them to give us the straight skinny on saturated fats. Here’s what they have to say:
Dietary fats (aka fats) are a large group of similar-molecules, and are one of the three major macronutrients (carbs and proteins being the other two).
Just like proteins are made up of amino acids, fats are made up of fatty acids. Fatty acids are characterized with long chains of carbon molecules strung together; when three of them come together, you get a triglyceride (you may have heard of that word before).
We’re about to make sense of a lot of fat terms you may have heard of, so read through this carefully.
Just like carbs and proteins can differ, so too can fats and their fatty acids. You have the much loved fish oil fatty acids – EPA and DHA. You have the overrated fat-burning fatty acid – CLA. You have olive oil and its magical Mediterranean oleic acid. You even have fatty acids that can literally give you heart lesions (erucic acid, which was genetically out of rapeseed oil). There is of course the universally reviled trans fat. Heck, even some of the up and coming supplements have fatty acids as their primary ingredient (such as royal jelly).
Because there are so many variations, we need a way of classifying them. There are three primary parameters:
How long the carbon chain is (short, medium, or long). You may have heard of coconut oil and its healthy MCT fat, aka medium chain triglycerides
- If the carbon chain has double bonds. Saturated fats have no double bounds, whereas unsaturated fats either have one (monounsaturated) or multiple (polyunsaturated, aka PUFAs).
- For unsaturated fats only, how the bonds are positioned. This is where we get trans fats from.
So even when we talk about just saturated fats, the length of the carbon chain can vary. There are 10 saturated fatty acids common in our diet, and thus it’s not easy to just “talk” about saturated fats – we are talking about different molecules that can have different effects!
It’s also hard to test out the effects. For example, if you replace carbs with fats and note a change, was it due to the introduction of fats, or due to the exclusion of carbs?
Cardiovascular Health
Studies on saturated fat intake and cardiovascular health tend to follow groups of people over time and survey what they eat. When people in that group are found to have some cardiovascular issue, we try to analyze the data to figure out what could have caused the issue. This is called an epidemiological survey.
There are many meta-analyses on these surveys already conducted, and they generally state:
- Just looking at people who eat saturated fats vs those who don’t, you have a higher risk of cardiovascular disease (CVD) if you do eat saturated fats. This is without analyzing any other details.
- When we analyze the rest of people’s diets, saturated fats do not associate with CVD1,2.
- Saturated fats do increase LDL cholesterol, but that increase does not correlate with an increase in CVD3.
- When you tell people to avoid saturated fats, they also tend to reduce refined carb intake. This reduction of processed carbs could be the reason why CVD risk decreases4.
To simplify, we know that constantly eating fast food will likely give you heart disease. As the burger is the main component, it gets blamed, and from that, the fatty acids are blamed. The actual culprit is either the buns and fries (with the burger), or some kind of negative interaction between the burger’s fatty acids and the bun/fries’ processed carbs.
Body Fat
We know that fat is more satiating (makes you feel more full) than carbohydrates5. When saturated fats are actually compared with PUFAs (plant based) or other monounsaturated fats, the satiety is equivalent6,7,8. While these studies did not measure weight over time, there were controlled interventions and suggest no significant effect of saturated fats here.
Fats tend to suppress appetite, but saturated fats have no additional suppressing-benefits than other fatty acids.
Now, a particular subset of ‘saturated fatty acids’ includes the medium chain triglycerides (aka MCTs). This term refers to the saturated fatty acids between 8 and 10 carbons in length and tends to refer to lauric acid, myristic acid, and caprylic/capric acid. In short, these are the fats that have made coconut oil very popular.
When looking at studies on coconut oil or MCTs in particular, there does appear to be slight weight loss effect when compared to other fatty acids. It should be noted that this happened when you replaced existing fat consumption with MCT fats, not just adding more calories to the diet. Still, it should be explicitly noted that the weight loss benefits were minimal. In fact, a good article and summary on this topic to read on this topic would be Bryan Chung’s “The lime in the coconut is purely optional” where he conducted a personal and small meta-analysis on studies and did find a weight loss effect, but it was pretty small.
There may be positive effects on weight loss associated with coconut oil/MCT fats, but the overall effect is pretty small and would likely only benefit weight loss if these fatty acids replace other fatty acids while calories are kept constant. The effect is too small to overcome the caloric content of the fatty acids themselves
Testosterone
A major claim for saturated fats for athletes and people looking to lose weight is that they can stimulate the production of androgens and other steroid hormones, which then promote beneficial changes in body composition.
Similar to appetite suppression, having an intake of dietary fat appears to be better for steroid hormone production than a low intake of fatty acids. Cohorts with lower fat intake have less androgen levels9. Testosterone can be either reduced by putting men on a low fat diet10 or increased with a high fat diet11. Still, the magnitude of change is roughly 12-13%, which may sound impressive, but is quite a small amount. To compare, testosterone injections usually give you 100%+ more testosterone12 although some studies have noted up to 400% at peak levels with testosterone itself13 We should note that this is for medically supervised therapy; steroid cycles are likely much higher.
Despite the above evidence, there is actually no well controlled interventions assessing the saturated fatty acids versus other fatty acids. When we look at survey research there doesn’t appear to be any promising correlations14. If there is a promising correlation, it seems to be with monounsaturated fatty acids15.
Fatty acids themselves increase testosterone when in surplus in the diet (when compared to a low fat diet), but the change in testosterone is actually pretty small. When looking at saturated fats in particular, there is no evidence to suggest that they are somehow better than other fatty acids.
Parting Thoughts
Overall, we can confidently state that saturated fats are not much better or worse than other kinds of fats. The worry that saturated fats will cause cardiovascular harm is mostly unfounded, but they don’t appear to give significant benefits either. Their role in testosterone production is overrated, and if there are any fatty acids you should keep an eye on, they would be the omega-3 and omega-6 fatty acids.
About Sol Orwell and Examine.com
Sol Orwell is the co-founder of Examine.com, where he and his team collate scientific research (over 22,500 citations) on supplementation and nutrition. Sol is also the creator of the Supplement Goals Reference Guide.
About Examine.com’s scientific supplement and nutrition guide:
Finding accurate supplement information today – especially online – is like walking through a mine-field. Most supplements are scams, some can harm you and the claims for the few that are safe and effective are usually exaggerated. I don’t sell or recommend supplements, and frankly, I hardly take any. But if you take supplements now or you have any interest in finding the few that actually work, you need to depend on science, not hearsay or personal testimony. That’s why you see so many evidence-based fitness progressional recommend Examine’s supplement guide scientific evidence. You can learn more at: http://examine.com/store/reference/
References
- Siri-Tarino PW, et al. Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr. (2010)
- Ravnskov U. The questionable role of saturated and polyunsaturated fatty acids in cardiovascular disease. J Clin Epidemiol. (1998)
- Mozaffarian D. The great fat debate: taking the focus off of saturated fat. J Am Diet Assoc. (2011)
- Kuipers RS, et al. Saturated fat, carbohydrates and cardiovascular disease. Neth J Med. (2011)
- Lomenick JP, et al. Effects of meals high in carbohydrate, protein, and fat on ghrelin and peptide YY secretion in prepubertal children. J Clin Endocrinol Metab. (2009)
- Cooper JA, et al. Impact of exercise and dietary fatty acid composition from a high-fat diet on markers of hunger and satiety. Appetite. (2011)
- Maljaars J, et al. Effect of fat saturation on satiety, hormone release, and food intake. Am J Clin Nutr. (2009)
- Kozimor A, Chang H, Cooper JA. Effects of dietary fatty acid composition from a high fat meal on satiety. Appetite. (2013)
- Hill P, et al. Diet and urinary steroids in black and white North American men and black South African men. Cancer Res. (1979)
- Wang C, et al. Low-fat high-fiber diet decreased serum and urine androgens in men. J Clin Endocrinol Metab. (2005)
- Dorgan JF, et al. Effects of dietary fat and fiber on plasma and urine androgens and estrogens in men: a controlled feeding study. Am J Clin Nutr. (1996)
- Snyder PJ, Lawrence DA. Treatment of male hypogonadism with testosterone enanthate. J Clin Endocrinol Metab. (1980)
- Snyder PJ, et al. Effects of testosterone replacement in hypogonadal men. J Clin Endocrinol Metab. (2000)
- Nagata C, et al. Relationships between types of fat consumed and serum estrogen and androgen concentrations in Japanese men. Nutr Cancer. (2000)
- Volek JS, et al. Testosterone and cortisol in relationship to dietary nutrients and resistance exercise. J Appl Physiol. (1997)
Copyright Sol Orwell and Burn the Fat Blog.com. Do not copy
Great article on a common misconception. Kudos to Tom & crew for bringing Sol & Examine.com in, they’re great.
Thanks for covering this topic! I have really embraced saturated fats after following a primal approach combined with IF. Think bacon, pastured butter, and buffalo wings!
I am starting to become aware (through reading) of how in recent history we (in the west anyway) have stopped eating the whole animal. The push has been for us to only eat muscle meat and lean cuts at that.
I would like to see your take on gelatine and how / if adding that in to the diet can be of benefit. There are companies that produce it for supplementation purposes and there are the obvious sources like pork rinds (yum), wings, bone broths…
I’ve always believed that the biggest culprits in the diet relating to fats were hydrogenation, emulsification and homogenisation. It is almost impossible to find milk that has not been homogenised (at east here in the UK), whereas in the fifties and sixties almost all milk sold was non-hydrogenated.
I am particularly dismayed at the increased use of “low-fat” spreads which use both hydrogenation and emulsification extensively.
As an aside, I recommend anyone who hasn’t already done so to check out the work of Hugh Macdonald Sinclair and his Inuit diet experiment, demonstrating the importance of EFAs and fish oils.
Sorry that should read ” whereas in the fifties and sixties almost all milk sold was non-homogenised”. :(
Take a look to this, please:
http://ajcn.nutrition.org/content/92/2/458.full.pdf+html
It seems tha the Meta-analysis from Siri-Tarino could have some potential limitations.
Jordi, that’s the good thing about getting your information from peer-reviewed scientific journals directly and not from second hand sources or media reports about the research… sometimes something gets lost in translation or interpretation when reported in the media, personal blogs, etc. Through peer review, the information gets vetted and continues to be studied. It is still being studied and each piece of research – even meta analyses – simply add to the body of evidence and help experts make recommendations or develop best practices. it doesnt say this is the final word or the end of discussion.
In that letter to the editor, the author mentions that the media gave that meta analysis a lot of coverage when it first came out. The wrong message may have come out in translation. If someone interprets this is “saturated fat is actually good and i should eat more” or “i can eat all the saturated fat I want” and they go out and start eating fat and chugging oil by the jarful, along with eating so much fat that it displaces other important fats, macronutrients and micronutrients, that could actually cause or aggravate health problems – not to mention make you fat from all the excess calories (see:https://www.burnthefatblog.com/archives/2013/03/coconut-oil-health-and-fat-loss.php)
To me, I don’t see this emerging data leading to a conclusion to “eat all the saturated fat you want.” I dont see Sol’s article drawing that conclusion either. I see this as saying, “wait a minute – the saturated fat and heart disease relationship is more complicated than pointing the finger at one type of fat or one macronutrient as the sole cause of the problem… there are other confounding factors… and it depends on context.” For example, what else is in the diet – trans fats? Not enough omega-3s, imbalance of fatty acids? too many calories? too much sugar? (fat + sugar)???
still plenty of questions, but some old assumptions are being questions and the picture is starting to get a little clearer.
I havent seen the good/ smart nutritionists, registered dieticians saying, “eat a high sat fat diet and chug coconut oil” but ive sure seen a few extremists selling those types of ideas and using this line of research as “proof”. In fact, I havent seen many of the good nutrition folk change their recommendations much at all other than saying, “go ahead have some whole eggs, and eat some saturated fat in balance with the other fats (example 30% fat with 10% mono, poly and sat fat), and in balance with other macros and in the right calorie range for you.” Ie, no need to demonize, but as best practice, keep it all in balance, unless you really know what youre doing otherwise! This may look like a lot of science to sort through, but on the other hand healthy eating and eating for fat loss really isnt rocket science
Maybe I will get sol or one of the research team at Examine to chime in further, but hope that helps!
Tom.
Thank you for your replie Tom!
I agree 100% with it. Great Job!
Cheers!
Nothing new for us people who do keto, glad to see it studied more.
As for reference, I’ve been ketogenic for over +12 years, while having 3 whole eggs for breakfast, along with ham, bacon or avocado, every single day and my heart is in incredible condition.
Also, I lift a lot and keep a low bodyfat level (below 10%) all year round, by eating fat.
Same here. Except that I can’t stay on keto for too long,but for me keto is the best way to lose fat, stay healthy and feel great at the same time!
It appears that not too many people are excited about these Saturated Facts !If only more people would understand that Zooming away from Saturated Fats has the power to increase their *Blood Flow* and allow their arteries to *Dilate* better so they can *FOCUS* on *EFAs* (:
Pretty good overview on saturated fat.
A small point of feedback:
The authors state:
“….. the medium chain triglycerides (aka MCTs). This term refers to the saturated fatty acids between 8 and 10 carbons in length and tends to refer to lauric acid, myristic acid, and caprylic/capric acid…..”
The authors mention “lauric acid”, but that is a 12-carbon fatty acid, and state that MCTs are only 8-10 carbon. Might this confuse some people who are new to learning about saturated fats (and at whom this article appears to be targeted at)?
Very interesting about fats and testosterone production. I really thought it would have had a bigger effect. Tom is right about studies being totally skewed by the media – they seldom get the translation right; and most of the time it’s not even close. Great article – a real eye opener!
Jay
Dietary fats and health: dietary recommendations in the context of scientific evidence.
Lawrence GD.
Although early studies showed that saturated fat diets with very low levels of PUFAs increase serum cholesterol, whereas other studies showed high serum cholesterol increased the risk of coronary artery disease (CAD), the evidence of dietary saturated fats increasing CAD or causing premature death was weak. Over the years, data revealed that dietary saturated fatty acids (SFAs) are not associated with CAD and other adverse health effects or at worst are weakly associated in some analyses when other contributing factors may be overlooked. Several recent analyses indicate that SFAs, particularly in dairy products and coconut oil, can improve health. The evidence of ω6 polyunsaturated fatty acids (PUFAs) promoting inflammation and augmenting many diseases continues to grow, whereas ω3 PUFAs seem to counter these adverse effects. The replacement of saturated fats in the diet with carbohydrates, especially sugars, has resulted in increased obesity and its associated health complications. Well-established mechanisms have been proposed for the adverse health effects of some alternative or replacement nutrients, such as simple carbohydrates and PUFAs. The focus on dietary manipulation of serum cholesterol may be moot in view of numerous other factors that increase the risk of heart disease. The adverse health effects that have been associated with saturated fats in the past are most likely due to factors other than SFAs, which are discussed here. This review calls for a rational reevaluation of existing dietary recommendations that focus on minimizing dietary SFAs, for which mechanisms for adverse health effects are lacking.
For me-HERO
Great post! Thanks