Confusion, controversy, and many questions abound around fat.
- Will eating fat make you fat?
- Which fats do you need more or less of?
- What types of fats drive you to eat more and are more likely to end up on your belly and bum?
- Is there such a thing as ‘good fats’ vs ‘bad fats’?
- Do dietary cholesterol and saturated fat go straight to your arteries?
To clarify some of the questions listed above, this article will use our analysis of 125,761 days of food logs from 34,519 Optimisers to bring you data-driven answers to these FAQs.
- What Causes Satiety?
- So, Does Eating Fat Make You Fat?
- Fat vs Carbs
- Changes in Fat Intake
- Fat and Diet Quality
- ‘Good Fats’ vs ‘Bad Fats’
- Omega-3 Fatty Acids
- Do Saturated Fats Cause Weight Gain?
- Monounsaturated Fat
- Omega-6 Fatty Acids
- Trans Fats
- Fatty Acid Ratios
- Saturated:Unsaturated Fat Ratio
- Fatty Acid Stretch Targets
What Causes Satiety?
But to understand whether or not fat keeps you full, we first need to explain what makes someone feel full or satiated.
If you haven’t read our master satiety analysis, here’s the TLDR: eating more nutrients—especially protein—per calorie is aligns with greater satiety.
Additionally, other vitamins and minerals have been shown to elicit somewhat meaningful satiety responses. Hence, consuming more nutrient-dense foods will keep you fuller for longer.
For our latest deep dive into satiety and nutrient leverage, check out The Cheat Codes for Nutrition for Optimal Satiety and Health.
First, let’s start with looking at fat as a macronutrient.
In the chart below, we have broken up the Optimiser data into various ‘buckets’ based on the percentage of total energy they are consuming from dietary fat (fat %) and then looked at the average energy intake within each ‘bucket’. We see that a higher fat intake aligns with a higher energy intake, and moving from 82% to 22% fat aligns with a 37% reduction in calories.
The chart below shows the distribution of fat % amongst our Optimisers, with the average Optimiser consuming 47% of their total calories from fat. While there is a large distribution, our Optimisers tend to consume a slightly higher fat diet than the general population’s fat intake of 43%.
Fat vs Carbs
That said, fat is not necessarily a better or worse energy source than carbohydrates; they’re both simple carbon-carbon structures that your body breaks to generate energy in the form of adenosine triphosphate (ATP).
As shown in the chart below, reducing either non-fibre carbohydrates or fat will both reduce the amount of energy you consume. So, you can reduce carbs, fat, or a combination of the two if you’re trying to lose weight.
Changes in Fat Intake
Many people noticed the climbing obesity rates and increase in carbohydrate consumption between the 1960s and 2000s and correlated the two to one another. This resulted in many experts pointing the figure at carbs as the culprit.
However, the reality is that our fat intake has been rising steadily for the past century. The increase in both of these macronutrients simultaneously is likely responsible for our population’s weight gain.
But this massive increase in fat is not due to people adding a bit of olive oil to their garden salads. These extra calories are quietly hidden in baked goods and ultra-processed foods from industrial seed oils like palm, canola, soy, rapeseed, cottonseed, and corn.
For more info, see How the Biggest Trends in Nutrition Influence How We Currently Eat.
Fat and Diet Quality
The chart below shows the relationship between fat and our Diet Quality Score. Because isolated fat sources like canola, olive oil, coconut oil, and butter tend to contain fewer micronutrients per calorie, reducing fat tends to increase nutrient density. However, protein—which is a dense source of micronutrients—tends to come packaged with energy from fat, which means it is not necessarily optimal to minimise fat in its entirety.
To compare, an optimal Diet Quality Score aligns with a diet consisting of 10 to 20% of total calories from carbohydrates. So, if you’re like most people who consume a similar low-protein blend of fat and carbs, you can increase satiety and nutrient density by reducing your energy from carbs OR fat or both while prioritising protein.
‘Good Fats’ vs ‘Bad Fats’
Many people today prefer unsaturated fats that mainly come from plants and shun animal-based saturated fat. Meanwhile, others prefer saturated fat and are staunchly opposed to industrial seed oils. However, we can see in the graphic below that most foods contain a mixture of different fats. Hence, it’s impossible to avoid one type of fat altogether.
In the following sections, we’ll dive into the data to see which fatty acids align with greater satiety and a lower energy intake and which align with eating a lot more.
Omega-3 Fatty Acids
Omega-3 fatty acids are essential; we must consume them directly from our diet to sustain life because we cannot synthesise them. Omega-3 fatty acids are named for their double bond at the third carbon position of the molecule.
While plant-based foods contain some omega-3s as alpha-linolenic acid (ALA), humans are not good at converting it to more bioavailable forms, like docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). In fact, the conversion rate from ALA to EPA or DHA can be as low as 0.5 to 5% and 1-10%, respectively. Hence, we have a better chance of absorbing omega-3s from fatty fish and other seafood.
Satiety Response to Omega-3s
The satiety response curve below shows that we tend to eat 25% fewer calories when our diet has more omega-3s per calorie.
Based on this analysis, we have set our Optimal Nutrient Intake (ONI) at 6.0 g/2000 calories for omega-3, which is more than five times the Dietary Reference Intake and twice the average intake of our Optimisers. We developed our ONIs as stretch targets that our data analysis has shown to be associated with greater satiety. For more details, see Optimal Nutrient Intakes (ONIs) for Satiety and Health.
Omega-3s are undoubtedly essential. But before you reach for the supplement bottle, keep in mind that you’re unlikely to see the same satiety and health benefits from supplements as you would from whole foods. Foods high in omega-3s provide many other beneficial nutrients. Hence, you should do everything possible to meet your omega-3 target from whole foods like those listed below.
Omega-3-Rich Whole Foods
- caviar (23%)
- sardines (7%)
- oyster (6%)
- salmon (5%)
- mussels (5%)
- tuna (2%)
- Shrimp (2%)
- scallops (2%)
Cholesterol is a controversial nutrient with a chequered history. While the 1977 Dietary Goals for Americans admonished us to minimise cholesterol, the 2015 Dietary Guidelines for Americans quietly removed it from the list of nutrients warranting concern.
Since the 1950s, it was believed that dietary cholesterol directly correlated to blood cholesterol, which was associated with heart disease. On this basis, the American Heart Association set a limit on cholesterol of 300 mg per day. Since then, the US population has dutifully reduced their dietary cholesterol intake.
In reality, we produce 85-90% of our bodies’ cholesterol needs whether we consume it from food or not. This is because cholesterol is essential for human function, and we need it to build our cell membranes, make hormones, and produce bile acids.
Change in Cholesterol Intake
The chart below from the USDA Economic Research Service shows how the cholesterol in our food system has declined since the 1950s. However, it doesn’t appear that reducing cholesterol has slowed the obesity epidemic; it seems to be quite the contrary!
Satiety Response to Cholesterol
Our satiety analysis shows that foods containing more cholesterol tend to be more satiating. We tend to consume 39% fewer calories when we consume foods that contain more cholesterol per calorie! Our multivariate analysis also shows a statistically significant satiety response once all the other essential nutrients—including protein—are considered.
Interestingly, the maximum cholesterol target (i.e., 300 mg/day) set by the American Heart Association and previous versions of the Dietary Guidelines for Americans aligns with the lowest satiety response!
There’s no need to go out of your way to drink butter or coconut oil to get more cholesterol; these foods are not nutrient-dense and do not contain the full complex of nutrients that often accompany other cholesterol-containing foods. Hence, there is no need to avoid foods like eggs, liver, and seafood that contain cholesterol alongside a matrix of many other beneficial nutrients.
Some popular foods that contain more cholesterol include:
- egg yolk (3.0%)
- liver (3.0%)
- whole egg (2.3%)
- caviar (2.0%)
- shrimp (1.6%)
- oyster (0.7%)
- fish oil (0.5%)
- cod (0.5%)
- pork (0.4%)
For more on cholesterol, see Cholesterol: When to Worry and What to Do About It.
Do Saturated Fats Cause Weight Gain?
Saturated fat is another type of fat demonised by the Dietary Guidelines. However, you may be surprised that saturated fat consumption has declined since the 1930s, dropping from 42% to 31% of all fat consumed.
Satiety Response to Saturated Fat
When it comes to saturated fat, our satiety analysis tells an interesting story.
- To the left of the following chart, we can see that we are more likely to eat fewer calories when we consume a lower intake of saturated fat vs a moderate intake of saturated fat.
- However, there seems to be a tipping point when we consume more than around 35% of our total calories from saturated fat. Hence, foods like cheese, meat, and eggs that contain a high amount of saturated fat tend to be more satiating. These foods contain protein, too.
Foods Rich in Saturated Fats
Some examples of popular foods that contain more saturated fat include:
- coconut oil (83%),
- butter (57%),
- lard (47%),
- Parmesan cheese (33%),
- bacon (33%),
- ground beef (27%),
- Brazil nuts (22%)
- eggs (20%)
While you probably don’t need to go out of your way to add butter and coconut oil to everything to prioritise saturated fat—especially if your goal is weight loss—this data indicates that there is no need to actively avoid nutritious foods like eggs, cheese, and meat that contain this ‘hazardous’ fatty acid.
Professional medical organisations often laud monounsaturated fat as the ‘heart-healthy’ fat. These fats are abundant in seed oils, like canola, soya, cottonseed, rapeseed, and other vegetable oils. But unlike omega-3s, cholesterol, and saturated fat, consuming more monounsaturated fat aligns with a greater calorie intake and is less satiating.
Satiety Response to Monounsaturated Fat
People consuming more monounsaturated fat eat 17% more calories than those who limit their intake of this nutrient to around 11% of their calories.
It’s interesting to point out that these ‘heart-healthy’ fats are often the main ingredients in hyper-palatable processed foods, like cakes, cookies, and doughnuts.
Change in Monounsaturated Fat
The chart below shows how our consumption of calories from various fatty acids has changed over the past century. We also plotted the US obesity rates alongside these rising calorie intakes, which have tracked eerily close to one another.
Since 1910—only a few years after the discovery of hydrogenation—our fat consumption has been climbing. Since then, we have added a whopping 700 calories of extra fat per day to our diets. Much of this extra comes from our increased intake of monounsaturated and polyunsaturated fats.
While shame and hatred are often directed towards saturated fat, our intake of this nutrient has only increased by a much more minimal 100 calories per person. The following chart shows the percentage of our total energy from polyunsaturated fat vs monounsaturated fat has steadily risen and continues to rise. In contrast, saturated fat rose until the 1960s and fell.
By now, you’re probably wondering where all this extra fat has come from. The following chart gives us a clue. Here, we can see the production of vegetable oils, mainly from palm, soybean, sunflower, and rapeseed, has increased eightfold over the past half-century!
Foods Rich in Monounsaturated Fats
- seed oils (i.e., palm, soybean, canola, sunflower, rapeseed, corn, cottonseed, etc.)
- olive oil
- avocado oil
- almond butter
- pistachio nuts
For more details on monounsaturated fat, see Monounsaturated Fat: Is It So ‘Good’ After All?
Omega-6 Fatty Acids
Omega-6 fatty acids are polyunsaturated fats primarily found in vegetable oils, nuts, and seeds. They are also found in animal foods like meat. Grain-fed animal foods tend to contain more omega-6 fatty acids than their grass-fed counterparts.
Satiety Response to Omega-6 Fatty Acids
While some omega-6 fatty acids are essential for human life, our satiety analysis indicates that a greater omega-6 consumption aligns with a higher calorie intake.
Additionally, a higher proportion of omega-6 fatty acids to omega-3 fatty acids has correlated with increases in inflammation, calorie intake, and many chronic health conditions.
Omega 6-Rich Foods
- Brazil nuts
- pistachio nuts
- almond flour
- coconut oil
- whole egg
- Parmesan cheese
- cream cheese
Trans fats are an even more controversial fat than cholesterol, and mainstream recommendations limit trans fats to less than 1% of your energy intake. Trans fats are found readily in foods containing hydrogenated plant oils (i.e., margarine) or deep-fried foods. However, natural foods like meat also contain trace amounts of trans fats.
Satiety Response to Trans Fat
The satiety response chart below shows that we seem to eat less when our diet contains more energy from trans fats.
However, it’s important to distinguish between naturally-occurring trans fats and those that are industrially produced. For example, harmless naturally-occurring trans fats are present in dairy and animal products.
In contrast, humans create industrial trans fats by pumping hydrogen molecules into liquid vegetable oil, which changes their chemical structure and solidifies the oil at room temperature. Hence, industrial trans fats are high in partially-hydrogenated vegetable fats, which are found readily in deep-fried foods and baked foods like biscuits, cakes, pastries, and buns.
If you are already avoiding processed foods, your intake of industrially-produced trans fats will naturally be kept to a minimum. Likewise, naturally-occurring trans fats should not be a concern if you’re focusing on nutrient-dense foods.
Foods High in Trans Fats
Foods that contain dangerous trans fats that should be avoided include:
- vegetable oils (i.e., soybean, corn, sunflower, rapeseed, etc.)
- foods listing hydrogenated oils as ingredients
- fried foods
Meanwhile, foods that contain more naturally-occurring trans fats you needn’t be so concerned about include:
- ground beef (4%)
- butter (3%)
- Parmesan cheese (2%)
- liver (1%)
Fatty Acid Ratios
In several previous articles, like this one, we’ve noted that we consume the most energy when our diet consists of a similar mixture of carbohydrates and fat. Interestingly, we tend to see a similar trend when different types of fats are mixed.
Omega 6:3 Ratio
As shown below, we seem to eat the most when the omega 6:3 ratio of our diet equals or exceeds 3:1. Towards the left of this chart, we can see that minimising omega-6 intake while prioritising omega-3 aligns with the lowest calorie intake.
But practically speaking, it’s not easy to maintain a low omega 6:3 ratio, especially if you have limited access to wild-caught seafood or grass-fed meats. Hence, omega-6 fats dominate our modern diet, and omega-3s are much harder to come by.
The chart below shows the distribution of omega 6:3 amongst our Optimiser data. Here, we can see that only 35% of Optimisers consume at or below an omega 6:3 ratio of 3:1.
To reduce your omega 6:3 ratio, you should prioritise seafood and minimise your intake of foods that contain seed oils as ingredients. Seafood like fish, molluscs, and crustaceans are plentiful in bioavailable omega-3. While grass-fed animal foods like beef and lamb contain some bioavailable omega-3s, they are often overshadowed by the omega-6s that meat also provides.
Saturated:Unsaturated Fat Ratio
Similar to our saturated fat intake and the omega 6:3 ratio, we have also seen a spike in the saturated fat:unsaturated fat ratio.
As the chart below illustrates, we tend to consume 12% more calories when we consume foods with a similar blend of saturated fat and unsaturated fat. Hence, it seems we see problems when we combine large amounts of these fats, like in processed foods.
In minimally-processed animal-based foods, saturated fats are more prevalent. Hence, we would have gotten most of our calories from these foods during the winter when plants were less abundant.
In contrast, unsaturated fats are more prevalent in plant-based foods, which would have been consumed more in summer.
But thanks to modern food processing, we often combine these fats in ways that stimulate our appetite uniquely, and we have access to all of them year-round.
Fatty Acid Stretch Targets
The table below shows the various fat parameters discussed so far in this article in order of strongest satiety response. For reference, we’ve also included the average Optimiser’s intake and a stretch target based on the 15th percentile Optimiser intake that aligns with a lower energy intake based on our data.
|omega 6 (%)||17%||5.0%||2.1%|
|sat fat (%)||14%||17.4%||8.7%|
|trans fat (g)||7%||1.40||0.23|
|omega-3 fatty acids||-10%||2.60||6.00|
|omega 6:3 ratio||-26%||6.3||1.4|
|cholesterol (mg/2000 cal)||-39%||650||1,090|
Overall, satiety and fat intake correlate and reducing your fat intake significantly impacts satiety. But, at the same time, we see at the bottom of the table that prioritising whole foods with more cholesterol and a lower omega-6:3 ratio aligns with the most significant reduction in calories.
However, it’s unlikely that most people will want to—or be able to—micromanage their diet to this extent! So, instead of using an avoidance mindset, prioritising nutrient-dense foods that contain more pro-satiety nutrients like omega-3s without excess energy from fat or carbs will be plenty.
The practical implication of this analysis of the various fatty acids is that:
- You should prioritise foods containing more bioavailable omega-3 fatty acids.
- You don’t need to fear foods containing cholesterol, as they seem to align with a lower calorie intake.
- The production of vegetable oils, mainly from palm, soybean, sunflower, and rapeseed, has increased eightfold over the past half-century! Avoiding processed foods that contain these industrial seed oils as an ingredient may be a good general strategy to avoid ultra-processed, ultra-palatable, nutrient-poor foods.
- If you’re managing your total fat intake, the balance of saturated vs monounsaturated fats doesn’t matter much.