”Don’t eat that! It’s full of fat!”
”Oh this is okay, it’s a ‘good’ fat”
”You’ve all been lied to! Fat is the best thing ever.”
Dietary Fat is probably the most controversial nutrient in existence. It’s completely essential to health but it’s also synonymous with excessive body fat. If that wasn’t hard enough to get straight, we’ve had years of being told fat intake is to be limited in the extreme and now it’s in vogue to say that we’ve been lied to this whole time!
So what gives?
Is fat a necessary evil to be limited or is it the nutritional savior we’ve all been looking for? In this article we examine the myths about fat, define what fat is on the molecular level, and discuss how much should you be eating everyday in order to optimize your health, physique, and performance.
Myth 1 – First things first: Does fat make you fat?
Eat fat, get fat… or was it Eat fat, burn fat?
People don’t really know how to treat fats in theirr diets. Both of the aforementioned sayings are commonly spouted as nutritional “wisdom.” The first statement posits that if you eat fat, it stands to reason that it will easily be stored as body fat. The second statement suggests that if you eat fat, your body will be less likely to think it needs to hold onto it’s fat stores and will begin burning body fat for energy. Both of these ideas make some amount of sense, but which is right?
The answer is neither of these ideas are correct. The problem with b
oth of these trains of thought is that dietary fat (fats we eat) is not the same thing as body fat! Dietary is a nutrient that plays numerous important roles in the body, it’s not just the building block of muffin tops.
The main factor in controlling your body weight will always be energy balance. If you eat an extra 1000 calories from carbs or fats the result will be the same: an extra 1000 calories stored as body fat. Our bodies are quite efficient at not wasting energy from food and any excess energy will be stored as body fat, regardless of the source.
At the end of the day, you can eat high, medium, or low fat and control your body fat composition as long as you control the overall amount of calories you eat in a day. With that being said, you can leverage the composition of your diet (high/low/medium fat content) to increase the likelihood of long term adherence to your diet.
Myth 2 – Eating fat is bad for your health
For the longest time we’ve been told that eating a diet high in fat, particularly saturated fats, is bad for our health. In a 2010 meta-analyses researchers examined 21 studies spanning 5-23 years that looked at coronary heart disease and fat intake. They concluded that there was no significant evidence for concluding that dietary saturated fat intake is related to coronary heart disease or cardiovascular disease.
Rejoice and eat ALL the bacon!!!
Not quite. The studies examined were all epidemiological studies, which can provide great insight into patterns of behavior and disease spread but become less useful when determining the mechanistic cause of disease. Additionally, a common criticism of this study method in regards to studying diet trends is that these diets often require participants to self-report their food intake, and people tend to be wildly inaccurate when reporting their food intakes.
That doesn’t mean this review can’t help provide better dietary guidelines. In general, higher body fat percentages are correlated to an increased all cause mortality rate, meaning people with high body fat tend to have a high chance of dying for any reason, including cardiovascular disease. Dietary pertains to this fact because, at 9 calories per gram, fat is the most energy dense macronutrient and has the greatest potential to cause fat gain via energy surplus.
If we look at the claim that “fat is bad for you” under the lens of these two reviews we can say that fat is not inherently bad for you. However, dietary fat is very energy dense and can make it very easy to eat more calories than needed in a day which causes fat gain. In turn, that fat gain is bad for you. So…
Eat ALL the bacon!!! (As long as it fits within your energy needs).
Myth 3 – Eating high fat is the key to “hacking” your biology and becoming superhuman
Sometime around 2013 the idea of putting butter in your coffee became really popular. This isn’t a teaspoon either, people are putting between a half and a whole stick of butter into a cup! Besides making the creamiest cup of coffee ever, what in the hell is the point of this?
The point of putting 500 calories of buttery goodness into your coffee is that it can help you attain and maintain a state of dietary ketosis. This is achieved through the Ketogenic diet (keto). Advocates of the ketogenic diet often make grand claims that eating kept increases their mental clarity, gives them more energy for workouts, or supercharges their fat loss, but is there any truth to these claims? Well before we answer these, let’s dive into what keto is and isn’t first.
Essentially, our bodies run primarily on glucose (derived from carbohydrates) and this is especially true of our brains, those thinking sponges just suck up all the glucose and actually can’t run on much else. However, our bodies and brains have another option for energy if glucose becomes extremely scarce; ketones.
Our bodies can create ketones from fat when our carbohydrate intake is low enough to put our bodies in a state called Dietary Ketosis.
Now, this isn’t a “No pasta” kind of low carb diet. In order for your body to start converting fat to ketones, there must be as few carbs entering your body as possible. Typically, ketogenic diets are composed of 60-80% fat intake, and no more than 10% from carbohydrates. Additionally, a ketogenic diet is often paired with fasting for longer periods of time to facilitate the transition to running on ketones.
A lot of the claims about products like bulletproof coffee are intertwined with anecdotal reports of peoples experience with Keto. Many people report feeling more active, aware, and cognitively responsive when they’re in a state of ketosis, but do these claims hold up when tested in the scientific setting?
1. Boosting Mental Clarity
Research has shown that caffeine can greatly improve mood and boost mental performance, and MCT oil shows promise for reversing the mental slowdown that occurs during hypoglycemia in those with type-1 diabetes, mild cognitive impairments, or Alzheimer’s Disease.This seems to support bulletproof coffee’s claims, however there are two issues:
- The benefits seen directly from caffeine do not require added butter or MCT oils. A cup of plain black coffee or a simple preworkout supplement will yield the same results for 400-600 fewer calories.
- MCT oil can convert to ketones efficiently, and the research supports the claim that a ketogenic diet may help prevent and/or mitigate the effects of a neurodegenerative disease. However, research suggesting that ketosis will boost cognitive performance in normal adults used ketone supplements on rats in doses that aren’t feasible for human consumption (about 0.55 grams per pound of body weight). This equates to a 110lb person, with a $60.00 bottle of supplementary Keto salts would contain only get 6 clinically effective dosages.
2. Improve Workout Performance
The claim of “improves workout performance” is problematic because workout performance isn’t a simply defined idea. Performance for a CrossFit athlete is different than for an Ironman competitor and both of those are extremely different from a powerlifter.
For endurance athletes much of the research has shown that being in a state of dietary ketosis during training does improveperformance and stimulated loss of body fat in off-road cyclists, and also may increase peak VO2, however this is at the cost of greater oxygen consumption (aka reduced exercise economy). Given this, it is possible that a ketogenic diet may be a good idea for marathon runners, and other high endurance athletes.
These beneficial results do not appear to be shared by strength and power athletes. In a 6-week study in which athletes ate a ketogenic diet, both power output and peak VO2 decreased. Similarly, in another study athletes on a ketogenic diet experienced adecrease in sprint power output. Overall, a ketogenic diet does not appear to boost performance for athletes whose focus is in the domain of strength and power performance.
3. Speed up fat loss
If you want to sell anyone anything in health and fitness simply add “…and it’ll help you burn more fat!” to the end of your sales pitch. It works for sham wraps, pills, and in this case, for high fat diets.
However, there is a nugget of truth to this claim.
If you eat a ketogenic diet (no carbs) and become fat adapted, your primary energy source then becomes fat. By definition you are burning fat for energy and you will probably burn more fat than before. However, burning fat and losing fat are not the same thing. Burning fat simply means that you’re using fat as an energy source. If you’re eating enough fat that you never need to tap into your body fat for energy (aka eating more calories than you’re using), you can become a fat burning machine that isn’t losing any fat.
Losing body fat requires a sustained energy deficit through diet, there is no way around it. This is simply a law of nature. This can be done by restricting calories through carbs, fats, or both. The ketogenic diet, paired with a sustained calorie deficit, will absolutely yield fat loss results, but so will a conventional flexible dieting approach.
But can a ketogenic diet help lose fat faster?
A recent study showed that eating a ketogenic diet does increase the dieters metabolism. This suggests that eating a ketogenic diet can absolutely help lose body fat faster than a conventional diet, however, the increase seen was around 60 calories per day, which equates to roughly 1 piece of bacon.
In one meta-analysis, people on a ketogenic diet experienced greater fat loss than those on a low fat diet across 13 studies. Another review suggests that a ketogenic diet may also help in controlling hunger through suppressing the hormones that stimulate hunger, and thus provide an explanation for better fat loss results. The problem with these reviews is that many of the studies analyzed weren’t controlling for calorie intake, which is the primary determinant of fat loss. Given this, it’s reasonable to say that a ketogenic diet can help in long term fat loss in people that do not want to track their food intake and simply want a set of rules to follow for their diet.
The bottom-line on the ketogenic diet
So everyone’s saying they feel great and becoming superhuman on keto, but the science doesn’t really support that 100%. What’s going on? Well, a lot of these people are switching from processed chips and frequent drive-thru meals to calorie balanced meals that often include more vegetables than they were eating before. In short, they were eating like an ass before and now they’re not. So of course they’re going to start feeling better, it’s still a positive change for their health and wellbeing overall.
It’s not that the ketogenic diet is “bad science” or “debunked,” but it really isn’t anything special. Any diet can make you feel and think clearer, as long as it provides adequate nutrient intake from fresh foods. Any diet can make your workouts feel better as long as it’s providing the right type of fuel your body needs. Any diet can help you lose body fat as long as you are burning more energy than you are eating.
Now that we’ve gotten those myths cleared up, onto the big question…
What are Dietary Fats?
Dietary Fats are an essential macronutrient that contains 9 calories of energy per gram. All fats can act as an energy source for our bodies. Additionally, different types of fats carry out different functions within the body. Most fats are considered nonessential, because our body can synthesize them, however there are essential fatty acids that we cannot synthesize and need to get through diet.
You may have heard a lot of scienc-y sounding words associated with fats: lipids, omega-3s, polyunsaturated fatty acids, oils, etc…
Cholesterol are lipoproteins (Lipo = Fat, Protein = Protein) that make up a very small portion of our total fat intake. Cholesterol is found in animal products – dairy, meat, eggs – and comes in two forms. High Density Lipoproteins (HDL), aka “good” cholesterol and Low Density Lipoproteins (LDL), aka “bad” cholesterol.
Triglycerides are the typical diet fats that make up the majority of our fat intake. The word “triglyceride” is a description of it’s molecular structure: Glycerol (-glyceride) bound to three (tri-) fatty acid chains. Triglycerides are commonly described based on two main characteristics: Saturation and Chain Length.
Saturated and Unsaturated Fats
The word saturated describes a state in which something is “stuffed to the brim” – It has absorbed as much of something as it possibly can. Think of a towel; as long as you can make the towel wetter, it isn’t saturated, but dunk that towel in a bucket of water for a minute and it’ll get as wet as it’s going to get, no matter how much more water you use. At this point the towel is saturated.
Replace the towel with a chain of carbon atoms and the water with hydrogen ions, and now we’re talking about the saturation of triglyceride molecules. Saturation describes the bonds between the carbon and hydrogen atoms of the chain. Each chain consists of a long “spine” of carbon atoms which can bond to 2-3 hydrogen atoms based on its position in the chain.
When each carbon atom is bonded to as many hydrogen atoms as it possibly can the chain is saturated. That is, a saturated fat is a fat whose molecular structure is saturated with as many hydrogen atoms as possible, given the number of carbon atoms. Saturated fats tend to be solid at room temperature. Animal products – butter, meat, milk, etc… – tend to be rich in saturated fats.
When one or more of the carbon atoms is not bonded to as many hydrogen atoms as it can, it compensates by creating a double bond to one of the neighboring carbon atoms. So the chain is not saturated with as many hydrogen atoms as possible, given the amount of carbon atoms. When one of these double bonds is present it is called monounsaturated and when more than one are present it is called polyunsaturated. Unsaturated fats tend to be liquid at room temperature. Plant and fish products tend to be rich in unsaturated fats.
Unsaturated fats can also be described as cis- or trans- fats. This describes the orientation of the hydrogen atoms on either side of the double bond. When the hydrogen atoms next to the double bond have the same orientation they are in a cis configuration. When the hydrogen atoms on either side of the double bond have opposing orientations, they are in the trans configuration. Trans-Fats are produced by an industrial process called ‘partial hydrogenaiton’ and are better able to mimic saturated fats because of their structure (solid at room temperature). Higher consumption of trans-fats has been highly correlated with cardiovascular disease and it is generally recommended to avoid its consumption.
Fatty Acid Chain Length
Short Chain Fatty Acids (SCFAs) are fatty acid chains whose length is 6 or less carbon atoms long.
Medium Chain Fatty Acids (MCFAs) are fatty acid chains whose length is 7 to 12 carbon atoms long.
Long Chain Fatty Acids (LCFAs) are fatty acid chains whose length is 13 to 21 carbon atoms long.
Very Long Chain Fatty Acids (VLCFAs) are fatty acid chains whose length is more than 21 carbon atoms long.
Fatty acids with shorter chains tend to be absorbed faster and more efficiently than those with longer chains. The most common source of medium chain fatty acids is coconut oil, and most fatty acids found in the American diet are long chain fatty acids.
Good Fats/Bad Fats
It’s impossible to have a conversation about dietary fats without talking about “good” and “bad” fats. Normally, this conversation involves a close relative that’s had enough wine to decimate their food control and is shoveling guacamole into their mouth. But it’s fine, it’s a good fat.
We’re not going to have that kind of conversation.
Very few fats can be easily labelled as “good” or “bad” – most exist in some gray area on the moral spectrum. As we’ll see, it’s the dose that makes the poison. Most negative issues associated with certain types of fat result from their overconsumption. So again, the most important aspect of diet’s effects health and body composition to worry about is energy balance.
When it comes to “good” or “healthy” fats, the criteria for definition is pretty wide open. Omega-3’s (described in the next section) have a decent claim because they are essential to health, but besides that there isn’t really much clarity on what makes a type of fat “good.” The case is similar for “bad” or “unhealthy” fats. There is one clear example of a fat that should be completely avoided: Trans Fat.
Other than those two examples, the lines are not clearly defined. Saturated fats are often called “bad” fats, in fact it’s consumption has astrong link to breast cancer in women, and prostate cancer in men. However, the same research that shows the link to prostate cancer suggests that these associations may actually reflect differences in intake and/or metabolism, and that saturated fat may not be a direct cause. Once again, we come back to saying that the overall amount consumed is having a bigger impact on our health than the specific types we eat.
What About Fats Influences on Testosterone?
Note: If you want to dive down the rabbit hole on testosterone then you want to read my in-depth article that dives deep into the science of the masculine hormone here.
One of the harder to pin down myths in the fitness space is the association with fat and sex hormones (testosterone, estrogen). It’s hard to pin down because previous research has shown a strong correlation between HDL cholesterol and free testosterone, bodybuilders using steroid enhancement have said for years that there needs to be a high saturated fat content in the diet for the steroids to effectively make more testosterone, and greater omega-3 intake is even correlated with bigger testicular volume.
Does this mean that more fat will make more testosterone?
As we’ve said earlier, energy balance is key maintaining good health. Energy balance can easily be disrupted by eating lots of high fat foods without considering their overall calorie content (the same is true for sugar). In recent literature, obesity shows a strong correlation to low testosterone and the cause is suggested to be bidirectional – meaning that one can cause the other, and vice-versa. So if energy balance is not accounted for, then additional dietary fat intake will likely contribute to the problem, not the solution. If energy balance is in check and you are at a healthy body composition then a normal intake of fats and physical activity will probably increase total testosterone levels.
What Are Essential Fatty Acids?
Essential fatty acids are a class of fatty acids that our bodies cannot synthesize, thus it is essential we get them from our diets. There are two known essential fatty acids – Alpha-linolenic acid (ALA) and Linolenic acid (LA). ALA is a type of Omega-3 fatty acid that is converted into eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two more well known labels for Omega-3 fatty acids.
Omega-3 Fatty Acids and the brain
Research at the University of Waterloo in Ontario shows that long chain polyunsaturated fatty acids are necessary for proper brain development and proper functioning of the brain. In their experiment, rats that were deprived of Omega-3 fatty acids displayed significantly worse performance when navigating a water maze when compared to rats that had sufficient Omega-3 fats present in their diet.
They hypothesized that this detriment is due to DHA’s and EPA’s influence on the neurotransmitter systems, particularly dopamine, in the prefrontal cortex. The prefrontal cortex is responsible for planning behavior, problem solving, decision making, and controlling social behaviors.
Foods that are rich in DHA and EPA include nuts, leafy greens, and fish. That makes sense given all of these foods have reputations as being “brain” foods. Turns out, that’s not a clever lie by your parents to get you to eat healthier… Go figure.
According to a 2005 review by the University of Oslo, Norway the researchers suggest that the optimal ratio for Omega-3 to Omega-6 intake should be 1:4. Ideally, Omega-3 and Omega-6 intake should be roughly around 2400-4800 and 7200-1200 mg per day, respectively.
How much fat should you eat in a day?
According to the USDA, a healthy range of fat intake is 20-35% of your total calories. So how do we figure that out? (Please don’t say algebra, please don’t say algebra).
We figure it out WITH ALGEBRA! We’ll break it down to three easy steps.
Step 1: Estimate the amount of calories you need to eat in a day. You can use my handy calculator here, or you can just multiply your bodyweight by 14. For this example, we are going to say my estimated calorie intake is 2500 calories per day.
Step 2: Multiply your calorie goal by 0.20 and 0.35.
2500 cals * 0.20 = 500 cals
2500 cals* 0.35 = 875 cals
Step 3: Divide both of those numbers by 9 (because fat contains 9 calories per gram).
500 cals/9 cals per gram = 55.6 grams
875 cals/9 cals per gram = 97 grams
So that means for a 2500 calorie per day diet, a good range of fat intake is about 55 – 97 grams each day.
Fat Intake for Fat Loss?
You want to calculate the goal range of fat intake before you cut calories. So for our example, we know that 55 grams per day is probably the lowest amount I want to go to. I can then cut calories from carbohydrates or fats, as long as I keep my fat intake above 55 grams per day.
Additionally, some people enjoy dieting where they increase fat intake and drastically cut carbohydrate intake. This may not be optimal for everyone but for those that prefer this method it will work as long as total calories are accounted for.
The key takeaways on Dietary Fat
- Eating fat does not make you fat. Only a calorie surplus can do that.
- Certain types of fats are associated with health issues, this is largely due to their overconsumption. Trans fats are the only fat that should be completely avoided.
- Eating a high fat/low carb diet can put you into a state of ketosis, within which you will burn fat for energy. However, burning fat and fat loss are not the same thing.
- Dietary fat has 9 calories per gram.
- 20-35% of your total calories should come from fats.
- Good/bad fats is largely a myth. Most fats have health benefits when consumed in moderation.