The big fat lie: Eating fat does not make you fat nor promotes heart disease

Think eating fat will kill you?

Well, then you’re in for one big surprise.

Read on to learn the truth about fat.

In my opinion the biggest myth in the nutritional world is related to our beliefs about fat. Apparently, fat makes us fat, fat causes disease, and fat kills. Clearly we need to avoid fat at all costs. In fact, I would estimate that at least 90% of my relations try to avoid fat as a general rule for becoming/staying slim and healthy. Personally, I had a very fat restrictive until not very long ago.

Apparently, eating fat is bad because of two main reasons: 1) Fat makes us fat and 2) fat increases the probability of heart disease. Looking like Newman in Seinfeld isn’t exactly preferable in our societies and dying kind of sucks so we quickly get the picture and avoid eating fat. However, how confident are we really about these two reasons?

Bonus content #1:

Being fat doesn’t necessarily mean being unhealthy.

Eating fat doesn’t make you fat

What happens to the fat we eat? Is it immediately stored as fat in our bodies as soon as it’s consumed? Many of us think so. The short answer to this question is: NO, that’s not what happens. My high level overview of what actually happens goes as follows:

Fat is one of the two macronutrients the body prefers for fuelling itself (the other being carbohydrate). It’s a dense energy resource (9 calories pr. gram fat, carbs contains 4 calories pr. gram) and the body uses it for a number of important operations. When fat is digested and enter our blood stream it is used by the body for a number of different activities such as physical movement, organ activity, and structural functions like making cell walls.  If we do have more fat in our blood stream than what the body needs for such operations our bodies can store this fat for future use.

Advanced content #1:

The body uses not only carbohydrates and fat for fuel, it can also break down protein to glucose in a process called gluconeogenesis.

So, under what conditions do we have more fat in our blood stream than needed by the body? This can happen in primarily two ways: 1) If we have also eaten lots of carbohydrates or 2) If we simply have eaten too much fat. I guess you could say “Oh my god Bjarte is lying, fat DOES make us fat!”, but if you’re thinking that you’re being too impatient. If we have eaten carbohydrates and that’s the reason why our body decides to store parts of the fat we’ve consumed then it’s not fat that makes us fat, it’s the carbs (I will adress the effect carbohydrates can have on us in the next post). However, what about eating too much fat? Surely that’ll makes us all look like chunky mamas?

Of course eating too much fat can make us fat. It’s the wrong question to ask though. A much better question is “how likely are we to eat too much fat?” The answer is not very likely at all and here’s why. We rarely binge (eat lots) on fats. For example, when we eat a large burger with lots of cheese and bacon, or a nice rib-eye steak with lovely high fat, creamy mushroom sauce, etc. we can go hours without eating. The same is true for gorging on all that that delicious fatty stuff we eat during the festive period (during Christmas my dad, oldest sister and I pretty much have a competition each year to see who is able to eat the most lamb ribs!). Personally I can’t eat for three weeks after Christmas Eve…. On a more serious note though, our bodies definitely tell us to stay away from food for a while after eating a big, fatty, meal.

But what makes our bodies operate in this way? Why aren’t we able to eat one big meal after the other when we eat fatty meals? The research out there isn’t very consistent in this area unfortunately. In fact, we don’t fully understand what causes satiety. What we do know however, is that if we reduce our carbs intake and eat more fat our hunger is greatly reduced and we’re likely to consume less calories.

Advanced content #2:

Some of the true experts in the field of nutrition would argue that the question “How likely are we to eat more fat” is also the wrong question to ask. They would probably say that “What makes you want to eat more food than you need” is the right question. I agree with them and I will address this in later posts.

Let’s see if the data our there supports this argument. With all the low-fat propaganda that’s been out there over the last few decades I don’t expect a significant increase in % calories from fat consumption in our diets (please let me know if you have good data for European countries with regards to fat consumption over the last 50 years). Assuming all other things being equal (which admittedly doesn’t happen very often), we would not expect a drop in obesity rates.

Figure 1: [1] The figure above illustrate proportion of overweight people and proportion dietary fat in American diets. It seems as though Americans are reducing their relative fat intake and becoming fatter. Shocker.

Figure 2: [2] Past and projected overweight rates in nine OECD countries. The proportion of overweight people is increasing in all selected OECD countries

Figure 3: [3] Proportion of overweight people in Norway is unfortunately also increasing even though we’re not as fat as the rest of the OECD (yeah!)

The above proves absolutely nothing. However, the data does indicate that the low-fat propaganda hasn’t made us slimmer. At all. That’s all I’m going to say about fat and obesity for now. Let’s focus on the second part of the big fat lie: Does fat intake really promote heart-disease?

Eating fat doesn’t promote heart disease

The belief that fat leads to cardiovascular disease is based on some significant studies carried out around half a century ago. The arguably most important of these studies was Ancel Keys’ “Seven countries study”, a 20-year study of about 12,000 men between the ages of 40 and 59 from 16 communities in Italy, the Greek islands, Yugoslavia, the Netherlands, Finland, Japan and the United State. The study “proved” that there’s a correlation of fat intake and heart disease. Unfortunately, the study not only received lots of media and political attention. It even changed governmental food pyramids and it is one of the main reasons why so many of us believe in low-fat eating even today. Unfortunately, the study is flawed and its conclusions cannot be trusted. Look here if you want to read the details of why.

However, the fact that Ancel Keys study can’t be trusted doesn’t provide evidence for fats not being healthy. Consequently, we need to look at other studies. Over the last decades a vast number of randomized, controlled, human experiments (viewed as the most dependable research studies of the four main types [2]) have been carried out to investigate the link between fat intake an disease. The results are fascinating. Not a single study has found evidence that increased fat intake increases the rate of heart disease. Not a single one. Look at this excellent Swedish site for a collection of relevant studies (the list comes right after the header “Hjärtkärlsjukdom”).

Bonus content #2:

Another fact that is worth mentioning is that the prevalence of heart disease in the US, England, Norway etc. has been steadily declining the last few decades. While the exact reason for this decrease is not known, it is likely the result of a combination of factors such as lower rates of smoking, better diagnosis and treatment of high blood pressure, and better management of those who have cardiovascular disease.

Instead of whining about all the delicious foods we could have eaten over the last few years, let’s be happy about the fact that we can enjoy fats again! There are lots of fatty foods that I have consumed a lot more of since I understood the big fat lie. Examples include bacon, rib-eye steak, avocados, cream, cheese, butter, fatty sauces (which always reminds me of my grandmas fantastic sauces during my childhood), nuts & seeds etc. Just being able to fry my eggs in butter feels like heaven to me. Happy days!

Advanced content #3:

There are three things about fats that it’s important to know about beside the fact that you can enjoy fat going forward. 1) Try to avoid trans fats as much as possible as these fats aren’t good for you. Try to avoid eating lots of carbs and lots of fats in the same meal. 3) Begin to understand the importance of the omega 6 to omega 3 ratio.

Summary & key takeaways: Eating fat does not make you fat nor promotes heart disease

  • Eating fat doesn’t make us fat as the body uses fats for a number of important operations like fuelling the body, making cell membranes etc.
  • Eating fat doesn’t make us fat because it’s hard for us to overeat on fat as we get very full after having eaten a fat rich meal and we don’t feel like binging on fat. This is especially true if you are simultaneously eating few carbohydrates
  • No studies, except from flawed ones, show a link of fat consumption to heart disease

Until next time, make sure you smile and shake your head every time you hear that fats are bad for you. Also, do enjoy some delicious fatty foods and invite me for a nice fatty dinner!

Sources & acknowledgments

In particular I’d like to thank Gary Taubes, Peter Attia and Robert Lustig who all have inspired me greatly. I don’t know any of them personally but I know their work which put simply is outstanding. I highly recommend that you get to know what these guys are writing about.

Gary Taubes:

Peter Attia:

Robert Lustig:    (check out the video that made him famous)

[1] “A Call for Higher Standards of Evidence for Dietary Guidelines”

[2] “Obesity and the Economics of Prevention: Fit Not Fat”

[3] Anders Engeland, Folkehelseinstituttet 2003

The picture of the guy in the boat was borrowed from

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