DOES FAT MAKE YOU JACKED?

Fat intake for muscle gain and performance part 2

Steven Kemp
Aug 3, 2017 · 6 min read

After discussing fat intake and health here, in part 2 we’ll get to the meat of the matter. Does fat make you jacked?

Why do bodybuilders often go on low-fat diets? Does testosterone help with muscle gain? Can your fat intake contribute to a more anabolic hormonal profile?

Let’s see.

The low-fat myth

There’s a school of thought somewhere hidden in the bodybuilding sub-culture. It says that as long as you keep fat low when trying to build muscle, you won’t gain fat. I understand the concern. If you’ve dieted over a period of weeks or months, the idea that your recently revealed abs will soon be under a warm blanket of adipose tissue is less than appealing. But is there any truth to the idea that keeping fat super low will pay off with a leaner weight gaining phase?

Glycogen is your body’s storage form of carbohydrate. With a bit of diet and training manipulation, you can deplete it from your liver and muscles. From this depleted state, you can go wild with carbs without gaining much, if any fat. But, like most of the best things in life, this doesn’t last forever. The fat-free honeymoon period taps out once glycogen stores are maxed. This leaves some of the excess susceptible to conversion and storage as fat.

Pigging out

In a 4 day overfeeding trial, subjects ate 175% of their maintenance energy intake mostly from carbs. The conversion of carbohydrate to fat increased by 296%. While 296% sounds like a hell of a lot, it doesn’t amount to too much in the real world, but it is there.

A slightly longer term study compared 14 days of 150% energy intake with the excess coming either completely from fat or carbs. you can see that a “honeymoon period” does exist, but not for long. While excess fat is stored straight away, during carb overfeeding, the excess carbohydrate gets burned as fuel. The body up-regulates energy expenditure to pull this off. But, after 7 days, fat storage starts to catch up. At day 14, there was no difference between fat or carbohydrate storage. If you take bedridden people and force feed them carbs through a tube in their nose, you see the same thing. After 4 days of induced overfeeding, glycogen in the liver and muscles are full to the brim. The excess carbohydrate is then turned into fat. It has to go somewhere.

This process does cost some energy. So in a sense, you will burn more calories turning carbs into fat than you would be storing the fat from your diet. But it’s not enough to get excited about. In the long term, you don’t get to cheat the system.

Bodybuilders and anyone trying to pack on muscle will take longer than a couple of weeks in any “bulking” phase. Now that we know there is no lean gaining magic from a low fat intake, are there any benefits to eating more fat?

Fat and your hormones

You don’t need a scientific reference to point out the fact that supraphysiological amounts of androgenic anabolic steroids lead to increases in muscle size. My mum can tell you that. What people don’t often understand is really how effective AAS is. Want to gain more muscle than someone already hitting the gym? Take 600 mg of testosterone enanthate a week and never get off the couch.

But what about if you’re not juiced to the gills? Does a bit more testosterone within the normal range make any difference to muscle gain?

High normal vs low normal

While not quite as exciting as 600mg a week, there are examples of raising T-levels in regular people. Getting elderly, untrained men with low-normal levels of testosterone to high-normal using replacement therapy has been studied. It results in a non-significant increase in lean mass and a decrease in fat mass. Those guys didn’t even lift though. What happens if you compare a group of strength trainees with normal testosterone levels to a group with 10% under normal? The group with suppressed testosterone gain more fat and less lean body mass, that’s what.

At this point, it’s worth pointing out that lifting weights itself might increase serum testosterone levels without any real dietary intervention. Energy balance also plays a huge role. Overfeeding for as little as 3 weeks increases the levels of testosterone in your blood.

So a higher free testosterone level might contribute to more muscle mass. Although the effect will never, ever be as pronounced as going on gear. So what effect, if any, does fat intake have?

Does fat make you jacked?

In two studies on trained lifters, higher testosterone levels correlated with the amount of saturated and total dietary fat. Diets too low in fat impair the hormonal response to training. There is also a dose-response relationship between the amount of dietary cholesterol in the diet, and gains in lean body mass. While this might not seem like the most concrete of evidence, it points to not being too hasty in ditching the full fat for the 0% Greek yoghurt just yet.

Let’s not get ahead of ourselves though. Eating lardo and polenta uncia every day isn’t going to turn you into the Hulk. But, changing to a low-fat diet can decrease concentrations of sex hormones (1,2,3).

Cutting or bulking?

So saturated fat is awesome for weight gain right? Well, hang on. A study from Rosqvist et al actually tested this. They took a group of people and overfed them on saturated or polyunsaturated fat for 7 weeks. It turns out that the saturated fat group gained more liver and visceral fat (the bad kinds) and more total fat. The group chowing down on polyunsaturated fat gained more muscle. This is one study, but it’s enough to give us pause. The effect of saturated fat on your testosterone levels should definitely be considered during dieting. But when gaining weight, giving a slight priority to polyunsaturated fat could be a better bet.

Getting to the point

For muscle gain, more testosterone is better than less. If you’re natural and are in a slight surplus, your ability to manipulate your hormonal level through your diet may not be huge. It can still be relevant to someone who’s trying to maximise their ability to put on lean body mass over time.

Here’s a rundown of the main points this piece tried to address:

  • A low-fat diet won’t help you stay leaner in the long run.
  • There may be a positive effect from higher testosterone levels within the normal range on muscle mass.
  • Low-fat diets reduce levels of sex hormones when compared to a higher fat diet.
  • The type of fat in your diet is important, as well as the total amount.
  • Emphasise saturated fat during a dieting phase.
  • Emphasise non-saturated fat during a muscle gaining phase.

To sum this article up, don’t skimp on fat when trying to gain muscle or lose fat.

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