Last updated:

25 July 2023

Many people remain confused about dietary fat after it was demonized back in 1980s. Here are the facts.

why eating fat will not make you fat

Reading time:

9 min read

Fat is the most misunderstood macronutrient.

You can walk into any gym and meet people who either tell you to avoid it because it’ll go straight to your waistline, or people who tell you to shovel it in like there’s no tomorrow because it’ll actually help you to lose weight.

It’s no wonder most people feel lost when it comes nutrition.

So this article is going to clear up the confusion around dietary fat, and give you some proper numbers you can work with.

Now, I sit somewhere in the middle ground with regards to fat intake.

If you’ve followed my comprehensive nutrition plan, The Shred System, you’ll know that I advise you to eat a sizeable chunk of dietary fat each day; definitely not the type of thing you’d see on an old low fat diet from the 1980s, but also not the “dropping lumps of butter in your coffee” which has become trendy in recent years among twats bio-hackers.

I typically recommend setting your fat intake to 0.4 grams per lb of body weight, and towards the end of the program (when you’re leaner than you’ve ever been before) this decreases to 0.3g per lb.

It has been set this way for two reasons:

  1. It’s low enough to help you stay within your total calorie goals.
  2. It’s high enough to regulate production of testosterone and cortisol, which sets the stage for muscle growth by helping your body to recover from all of those hard sessions and take advantage of the protein you eat.

Let’s get stuck in…

Table of Contents

Fat: Why Such Confusion?

Does eating fat make you fat?

The fearmongering surrounding dietary fat dates back to the early 1980s.

It’s pretty normal for a macronutrient be demonized in the media (we’ve seen it happen to both protein and carbohydrates in recent years), but fat really took a beating in the 1980s, when the National Dietary Guidelines published research labelling it “the root cause of heart disease and obesity.” Ouch!

It caused mayhem.

Food companies scrambled to remove it from their products, but customers still wanted to eat junk food, and this kick-started the sugar craze which dominated the rest of the decade.

And then an even bigger problem arose…

You see, many food manufacturers were unable to replicate the great taste of their products by switching to a sugar-only version (because it’s not the fat or the carbs which makes junk food taste nice, but rather the combination of the two), and this led to the popularization of trans fat; a really nasty motherfucker of an ingredient. This man-made fat substitute was developed by German chemist Wilhelm Normann in 1901. It still has all of the calories of dietary fat, but it offers none of the nutritional benefits.

So by the mid-1980s, the cupboards of the population were either lined with foods which consisted entirely of sugar, or foods which consisted of a combination of sugar and trans fat!

But perhaps the worst part is that it was all for NOTHING.

It turns out fat was not the “root cause of heart disease and obesity”, as evidenced by the fact that obesity levels soared to record heights during a decade where it was taken out of most foods!

The real issue here was a case of unhealthy lifestyle choice across the board. The 1980s was a decade which saw the explosion of fast food, junk food, convenience food, and this, coupled with a meteoric rise in the number of people sitting on the couch being lazy fuckers, created a recipe for disaster.

This macronutrient received a long overdue apology in 2015, when a comprehensive meta-analysis from Scottish researchers slammed the original 1980 recommendations and declared that they were made without sufficient evidence. (1)

How To Optimize Your Fat Intake

how much fat should you eat per day to build muscle

As more years went by, and more studies were published, we have begun to see how beneficial dietary fat is – not just for general health, but also for muscle growth.

Specifically, the Omega-3 fatty acids found in fish (and commonly used in supplement form) have a huge list of benefits which include:

  • Increased muscle retention
  • Improved memory
  • Delaying the signs of aging
  • Enhanced mood
  • Lowering the risk of CHD (coronary heart disease)
  • Improved anabolic response to insulin (more muscle growth!)
  • And they even play a small part in the fat burning process. (2, 3, 4, 5, 6)

That’s quite a list, huh?! Here’s more on those.

So dietary fat is definitely something we can put to good use, and definitely something which deserves to be part of our daily diet.

There are four types of fat you can eat:

  1. Monounsaturated fat
  2. Polyunsaturated fat
  3. Saturatd fat
  4. Trans fat

The aforementioned Omega-3 fats are part of the polyunsaturated fats family, so we definitely want to be getting those bad boys, but the truth is you can eat a balanced diet containing the top three.

You might be surprised to see saturated fat up there, but there’s really no reason to cut it out of your diet. In fact, research shows that athletes consuming the proper amounts of saturated fat and monounsaturated fat are able to maintain higher levels of free testosterone, and considering that free testosterone has a direct link with how much muscle we are able to build, this is not something we want to miss out on! (7)

Don’t worry about striking a perfect balance (33% monounsaturated fat, 33% polyunsaturated fat, and 33% saturated fat), because this ins’t realistic for people who lead busy lives, just focus on getting plenty of variety into your daily diet and focus on hitting your overall fat goal.

Now let’s set your daily target.

I recommend setting your fat intake to 0.4 grams per pound of body weight.

This is low enough to easily fit within your calorie target, so your diet doesn’t need to feel restrictive, but high enough to ensure you reap the benefits it offers in terms of testoserone regulation, alongside increased production of the muscle building peptide hormone IGF-1 (insulin-like growth factor-1). There does not appear to be any performance-related benefits from going higher than this (other than using the calorie dense nature of fat to boost your calories if you’re trying to gain weight). (8, 9)

In recent years we have seen a steep rise in the popularity of very high fat diets.

It’s like every workplace has a guy who wraps all his food in bacon, and gives his meals macho names like bulletproof coffee, protein bombs, and ballistic soup. I do not recommend this approach. A 2018 a study from Norway showed us that following a very high fat diet can have a disastrous impact on our LDL cholesterol (a signpost for cardiovascular risk factors), skyrocketing it by 44%. That’s a crazy increase, but what’s perhaps even more crazy is the fact they achieved this in just three weeks. Yikes! (10, 11)

These findings were re-confirmed in 2021, when a study published in Nutrients advised:

“The elevated LDL cholesterol should be a cause for concern in any young, healthy, normal-weight women who follow a low carb, high fat diet.”

We want none of those risk factors, and all of the results.

A target of 0.4g per lb of target body weight would do that, so with this in mind, a person with a target body weight of 180 lbs would shoot for about 72 grams of fat per day. There are are 9 calories in one gram of fat, so that’s 648 calories. Adjust this figure to suit your target body weight.

A List Of Easy Fat Sources

Sylvester Stallone eating healthy fats for breakfast

Now that you’ve set your target, you’re good to go!

You’ll probably find it easy to hit your fat intake each day, because fat is often a secondary macronutrient in many protein-based foods (and you’ll already be eating plenty of those if you’re trying to build muscle).

But here’s a handy list you can use to identify foods to help you smash you targets if you need extra help.

I hope you’ve enjoyed reading this article, I certainly enjoyed writing it.

Nuts / seedsFat (per 100g)
Macademia nuts75g
Brazil nuts66g
Almond butter59g
Mxed nuts50g
Flax seed42g
LegumesFat (per 100g)
Peanut butter50g
Soy beans (cooked)9g
Edamame beans5g
FruitFat (per 100g)
Fish / sea foodFat (per 100g)
Arctic char12g
Crab cake8g
DairyFat (per 100g)
Cheddar cheese33g
Greek yogurt10g
Ricotta cheese10g
Cottage cheese4g
Whole milk4g
MeatFat (per 100g)
Lean ground beef17g
Filet mignon17g
Pork chops14g
Beef tenderloin8g
Cured ham8g
PoultryFat (per 100g)
Turkey breast17g
Lean ground turkey8g


  1. Harcombe Z., et al. Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983: a systematic review and meta-analysis. Open Heart (2015).
  2. Smith G. I., et al.Dietary omega-3 fatty acid supplementation increases the rate of muscle protein synthesis in older adults: a randomized controlled trial. Am J Clin Nutr (2011).
  3. Smith G. I., et al. Omega-3 polyunsaturated fatty acids augment the muscle protein anabolic response to hyperinsulinaemia–hyperaminoacidaemia in healthy young and middle-aged men and women. Clin Sci (2011).
  4. de Barros T. T, et al. DNA damage is inversely associated to blood levels of DHA and EPA fatty acids in Brazilian children and adolescents. Food Funct (2020).
  5. Yu Y-H., et al. The function of porcine PPARγ and dietary fish oil effect on the expression of lipid and glucose metabolism related genes. J Nutr Biochem (2011).
  6. Muldoon M. F., et al. Serum phospholipid docosahexaenonic acid is associated with cognitive functioning during middle adulthood. J Nutr (2010).
  7. Mínguez-Alarcón L., et al. Fatty acid intake in relation to reproductive hormones and testicular volume among young healthy men. Adian J Andol (2017).
  8. Heald A., et al. The influence of dietary intake on the insulin-like growth factor (IGF) system across three ethnic groups: a population-based study. Public Health Nutr (2003).
  9. Whittaker J., et al. Low-fat diets and testosterone in men: Systematic review and meta-analysis of intervention studies. The Journal of Steroid Biochemistry and Molecular Biology (2021).
  10. Retterstol K., et al. Effect of low carbohydrate high fat diet on LDL cholesterol and gene expression in normal-weight, young adults: A randomized controlled study. Atherosclerosis (2018).
  11. Buren J., et al. A Ketogenic Low-Carbohydrate High-Fat Diet Increases LDL Cholesterol in Healthy, Young, Normal-Weight Women: A Randomized Controlled Feeding Trial. Nutrients (2021).

Who Is Russ Howe PTI?


Russ has been a personal trainer in the UK since 2002, and provided both training advice and full programs on this website since 2011.

His work has been featured in Men’s Fitness magazine, and the content on this website led to him being voted one of the world’s top 50 fat loss coaches by HuffPost.

Russ spends his time coaching men and women inside the legendary Powerhouse Gym, South Shields, and writing training tips for the 114,301 members of his popular free training e-mail (join it below).

Responses to “Here’s Why Eating Fat Won’t Make You Fat”

  1. Phillip avatar

    TY for this post! I used to avoid fat like the plague during the 1990s, and it led to many problems for me when I got into my 40s. Since about 10 years ago I’ve moved out of that mentality that ‘fat is fat’ and feel like I’m happier and in better shape at 56 than before! TY Russ

  2. Cliff avatar

    HA yes i recall those ads in the 90s for fat free food which was loaded with sugar. The world, particulalry US, is paying the price for that lifestyle nowadays i guess.

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