Not in the way you might think, anyway.

Today, it’s hard to go to a grocery store and not run into food packaging that screams “Low-Fat!” or “Reduced Fat!” or any number phrases that just boil down to misleading packaging lies. Food producers do this because everyone knows that if you’re trying to lose weight, you have to cut out fat from your diet…right?

But if that’s true, and everyone has been cutting out fat to lose weight, why have obesity rates in the United States skyrocketed over the last 18 years?

It’s because it’s not the fat that’s making you fat.

Fat is just another nutrient source, same as carbohydrates and protein.  What makes you fat is taking in more energy (calories) in a day than you use.  That’s called being in a caloric surplus.

While this might seem like a somewhat challenging thought, fat isn’t solely to blame for weight gain, and it’s not fair to even say it’s a major factor in weight gain.  At fault is a confusing mishmash of terminology, the demonization of fat over the past generations, and a pesky little diagram that’s been imprinted in the minds of generations of Americans.

Let’s take a look at how fat got a bad rap to see what you really should be thinking about when you’re trying to lose weight.

Eating Fat Is Not the Same as Becoming Fat

Part of the reason people get the idea that the fat they eat makes them fat is because of the words we use to talk about it.  It’s really simple for a lot of people to just assume the fat in food as something that makes them gain fat on their bodies because we use the same word to describe two different things.



The fat that is stored by our bodies is more accurately called “adipose tissue.” Adipose tissue stores are made up of primarily adipocytes and are responsible, among other things, with storing excess energy for times when you’re not able to give your body the energy it needs in a given day.

Body fat by itself isn’t automatically bad: you need some fat/adipose tissue for survival. Anyone with a body fat percentage of 0% would not be alive. Even getting down to what’s called your “essential fat” – the fat needed to maintain a healthy and functioning body – can cause a whole slew of complications.

Take the example of bodybuilders, who in a sense could be defined as “professional body fat losers”. When bodybuilders get into competitive shape, they are required to lose as much body fat as possible in order to give their muscles definition and themselves the perfect-looking physique. Often, this can lead to some health complications that they don’t frequently advertise.

For example, in a 2013 study of a competitive male bodybuilder preparing for competition in which he was continuously observed 6 months prior to competing and 6 months after, the bodybuilder was able reduce his body fat percentage from 14.8% to 4.5% by the time of competition.

In the process of losing all this fat, the researchers noted some less than desirable consequences:

Of note, many of the physiological changes observed including an elevation in cortisol, reduction in testosterone, reduction in testosterone, reduction in immune function, alterations in mood status, and decreases in physical performance and maximal heart rate that occurred during the preparation period are consistent with markers of overtraining.

ROSSOW, ET AL (2013)

Having a mentality of having as little fat as possible isn’t the greatest mentality because even if you achieve very low body fat percentages like bodybuilders do, this doesn’t necessarily convey better health, and the process that you take to get there might not even be worth the long-term effects.

And with a very thin fat layer, you’ll probably be pretty cold too.


nutrition-labelBut of course, when you’re eating fat, you’re not eating adipose tissue. The fat you eat is dietary fat and is one of the three essential macronutrients your body can get energy from.

When we talk about calories, we’re actually talking about some combination of the three macronutrients: carbohydrates, protein, and fat.

Look on the back of a nutrition label. What do you see?

Although they’re not labeled as such, you’ll see the three macronutrients listed there – which we’ve underlined – along with the grams of each.  Each macronutrient contributes a certain numbers of calories to the total caloric content of the food.  Those are:

  • Carbohydrate: 4 calories per gram
  • Protein: 4 calories per gram
  • Fat: 9 calories per gram

You can actually multiply the grams by the calories and add them together to get the total calorie number listed at the top of the label (this one actually comes out to 232, but the government allows rounding to the nearest 10).

This bears repeating: fat is a macronutrient. It isn’t necessarily bad on its own.  Furthermore, you need dietary fat.  That’s because your body can make all the fatty acids it needs, except for two: linoleic acid and linolenic acid.  These two necessary substances have to be found in your diet.

Would you believe that people actually used to eat more fat than they do now and at the time obesity rates that were much lower? It’s true, they did, and it’s true – obesity rates used to be much lower.  So if increased fat isn’t making you fat, what is?

What’s Actually Making You Fat?

Too many calories, probably from carbs.

Eating more calories than your body uses and needs in a day causes you to gain weight, and Americans continue to eat more and more calories with each passing year.

According to the USDA, from 1970 to 2000, the total number of daily calories that Americans ate increased by530 calories, an increase of 24.5%. During the same time period, the percentage of Americans categorized as obese increased dramatically.

What happened?

A deliberate and significant dietary shift that can be traced back to a specific moment in time: the 1977 Dietary Guidelines for Americans.

Prior to the recommendations, which were distributed to the public in 1980, the suggested division of the amount of calories Americans had been receiving was:

  • 40% Carbohydrate
  • 40% Fat
  • 20% Protein

Up until the late 70s and early 80s, Americans had been advised to obtain calories from fat and carbohydrates in equal amounts. And, at the end of that period, the obesity rate among adults was around 13.4% (compare that to today today, where it hovers around 35%).

What change did the recommendations make? Among the suggestions were two major modifications to dietary macronutrient intake. These were:

  1. Increase calories from Carbohydrates from 40% -> 55% or 60%
  2. Decrease calories from Fat from 40% -> no more than 30%

Essentially, the Dietary Guidelines suggested that people eat less fat and get more calories from breads, grains, rice, pasta, etc. This was intended to protect Americans from weight gain and heart disease.

Does this “high carb, low fat” diet seem familiar and normal to you? Do you have some kind of carbohydrate present at every meal?  If so, it’s probably due to this image:USDA_Food_Pyramid_1024x1024

Released in the U.S. in 1992, the food pyramid was designed as an easy way for people to remember which foods they should be getting their calories from and the relative importance of each. Carbs were healthy and good, and so they formed the base; fats were bad and placed at the top.

Although this concept seems pretty normal to us now, at the time in the late 1970s it was actually considered quite radical – so much so that then-president of the National Academy of Sciences, Philip Handler, described the proposed shift as a “vast nutritional experiment.”

The results of this experiment? Unfortunately, a complete failure.  Here’s the change in obesity rates from 1962 – 2010

Beginning at around the time when the Guidelines were first recommended in 1977 and their release to the public in 1980, you can see the percentage of Americans classified as obese increase sharply as they followed the government’s advice to cut fat and increase carbs.

Some experiments fail. This was one of them.

Why did this happen? Americans started to eat more calories.  This is surprising when you consider that carbohydrates contain less than half the calories (4 Cal) that fat (9 Cal) does, gram for gram.

Shouldn’t shifting away from fats and towards carbs just reduce overall caloric intake, just by simple math?

It doesn’t work that way if you just eat more carbohydrates.

You see, consumption of a high carbohydrate diet can trigger something called “reactive hypoglycemia.”  This is a condition experienced by people who do not have diabetes and are otherwise healthy. Among its symptoms is a feeling of hunger.

Guess what’s the best way to make that hunger go away? Eat more carbs – your body will be craving them.  Andsince carbs were supposed to be the largest macronutrient source anyway, most people didn’t think twice about having a snack that consisted of bread, rice, or something else carb-heavy.


This is exactly what people did.  Of the 24.5% more calories that people started eating from 1970 – 2000, nearly 40% of that increase was due to grains alone, contributing to large increases in carbohydrate consumption and unnecessary extra calories.

By advising people to eat less fat and eat more carbohydrates, the government actually made the obesity problem far worse.  Recognizing the sharp increase in obesity, the food pyramid was revised in 2005 and ultimately retired in 2011 in favor of what the USDA now calls “My Plate,” which gives people a much better visualization of the relative importance of each food category by showing roughly how much space each should take up on a plate.

To be clear, neither carbohydrates nor fats on their own cause you to gain weight – it’s just that you tend to eat more calories when your diet is focused on carbohydrates over fat.  Being in a caloric surplus causes you to gain weight. A carb-heavy diet makes it very easy to be in a caloric surplus.

So I Can Throw Away the Low Fat Options?

If you’re smart about it, yes, but you still have to be careful.

Remember, it’s not the fat itself that’s making you fat; it’s the extra calories that you don’t need that makes you fat.  While it’s very easy to eat extra calories on a carbohydrate-based diet, it’s also very easy to add on extra calories from fat too.

At 9 calories, fat is the most calorie-dense macronutrient by far.  This means that if you’re looking to lose fat, the low-fat options are still fine choices – not because of their low fat content, mind you, but because of their lower caloric content.  

The fat isn’t making you fat due to just being fat; it’s the extra calories from fat (as well as all the macronutrients) that is causing you to gain weight.

What this means is, if you are responsible with your diet, you can choose foods that contain fat, guilt-free.  You just need to be smart about your caloric intake throughout the entire day.

For example, if you really like the taste of whole milk and have been forcing yourself to drink 1% milk because you think you’re supposed to, you can drink whole milk guilt-free so long as you know that that whole milk contains 46% more calories than 1% milk and you understand that you’re making a deliberate choice to get more calories from milk than from somewhere else.

This means that if you choose to get more calories from milk (and by extension fat), you have to cut calories elsewhere.  If you’re like most Americans, you can probably find foods containing carbohydrates, that if you’re being honest, you can probably do without.

The current (2015-2020) Dietary Guidelines for Americans agrees, as it does not encourage a low-fat diet any longer.  It even encourages a lower intake of carbohydrates by widening the percentage range for carbohydrates from 55-65% to 45-65%.

Ultimately, the only person who has any real influence on how you divide your nutrient intake/calorie limit is you.

A lot goes into planning, preparing, and following a diet. Trying to balance what you like to eat with what you should be eating to maintain a healthy weight and body composition can be tricky.  When you start keeping track of calories, things can get complicated easily.

However if you have a good idea of what your individual caloric needs are, which you can learn by using a combination of your Basal Metabolic Rate and your activity level, this will become a lot easier.

Understanding how fat and the other macronutrients make up these calories will only further ease the problems with designing a diet. Remember, fat isn’t bad on its own.  Focus on building a diet that you actually want to eat, keep it within a reasonable number of calories, add in more physical activity, and you’ll be closer to your weight loss goals than if you simply just reach for packaging that promises “low fat” or “reduced fat” foods.

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