Low Fat Or Low Carbs?

low fat or low carbs

So much conflicting weight loss advice…

The latest is the low fat or low carbs debate.

Today I’ll be looking into this for you.

Because a couple of weeks ago I was reading a newspaper at my brother Shaun’s house.

Not much in the sports section..

And then I saw it.

“New study proves low carb diets don’t work.”

I remember shaking my head at such a broad statement and making a mental note to go to town on it here on the blog for you guys when I got a moment.

Russ Howe PTI

Low Fat Or Low Carbs?

The headline in question was reporting the findings of a study published in Cell Metabolism.

The tabloids ran with the story that in a battle of low fat or low carbs, a low fat diet is the outright winner when it comes to weight loss.

It was actually a really well-conducted study which had some very interesting findings, which I’ll cover further down this post. (1)

But the first thing I wanted to say is this:

Stop villainizing certain food groups!

The best diet is the one you can stick to.

I couldn’t give a damn whether your diet is high in fat, low in fat, high in carbs, or low in carbs, there is one factor which over-rules all others – you must be in a caloric deficit to lose weight.

Going low fat doesn’t mean you are going to lose weight, and neither does going low in carbohydrates.

Heck, you could go low in carbs and actually gain weight if you were still consuming more calories than you were burning.

This is the same nonsense mentality which has been used for decades, which sees people alienate certain macronutrients – i.e. no carbs – before moving on to alienating whole food groups – i.e. no dairy – to moving on to alienating specific foods – i.e. no chocolate.

Then it’s only a matter of time before they’re raising their “better-than-you” eyebrow at all of their friends for daring to eat anything that doesn’t taste like cardboard.

It’s all bullshit.

So fuck the sensationalist headline.

low carb vs low fat

The Study In Question

A team of researchers from the National Institute of Health, Bethesdaas well as a few other locations, including right here in my beloved Newcastle Upon Tyne, UK – were behind this study.

Over the course of six day trial, 19 overweight individuals were placed on either a low fat or low carb diet.

  • the low fat group consumed 352g carbs and 17g fat per day
  • the low carb group consumed 140g carbs and 108g fat per day
  • protein was kept constant for all participants.


What’s The Problem?

There are a couple of issues which spring to mind here.

The first of which, you may be thinking “the study was only 6 days?”

But don’t worry.

While the length of the study was short, the detail was immense.

In fact, the reason it was kept short is because it would have been incredibly impractical – and costly – to continue for, say, a month.

Each participant in the study was kept in a hospital ward for the duration of the test.

low fat diet vs low carb diet

The second issue which you may be thinking is “that’s not low carb!”

And, well, you’d be absolutely right.

This is one of the reasons the tabloid headlines were just plain wrong.

You see, this was not a case of “low fat or low carbs” in the first place.

This study was actually created to see what effects were caused by restricting fat intake, not to directly pit low fat or low carbs against eachother to see who won.

What we really had here was a very low fat diet versus a kinda low carb diet.

While the fat diet was extreme at only 17 grams per day, the carb diet was pretty average.

It’s not uncommon for practitioners of low carb diets to drop their intake under 100 grams per day, a good 40 grams lower than we had in the study here.

They’d also increase their protein intake significantly higher than was used in this study to compensate for the drop in carbs – another factor which didn’t come into play here.

So the first takeaway point from this study is this:

Don’t believe everything you read.

The Bottom Line

Should you freak out that we need to go back to dieting 1980’s-style, where fat was deemed” bad for you”?

Of course not!

While the low fat group lost slightly more weight during the study – 0.5 lbs to be precise – it would be impractical and unsafe to copy the methods used here.

So much so, the researchers actually wrote a warning into the study’s afterthoughts discouraging people from attempting to use the same protocol in everyday life:

“Translation of our results to real-world weight-loss diets for treatment of obesity is limited since the experimental design and model simulations relied on strict control of food intake, which is unrealistic in free-living individuals.”

The low carb group were not really low carb – protocols like high carb days to prevent adaptation were not used either – and the low fat group were so low it would be dangerous to replicate in the real world.

Quite frankly, neither approach in this study as optimal for fat loss, because that’s not what the researchers were looking for, it’s what the media was looking for.

One interesting fact which came out of this study is the clear demonstration that cabohydrates are not “the enemy” – our low fat group here were eating over 350g carbs per day and still lost weight.

So stop fucking villainizing food groups!

What this study really proved is that a reduction in calories by 30% promoted weight loss.

That’s it.

low carb diet

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1. Hall, K. D., et al. “Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity.” Cell Metabolism, Volume 22, Issue 3, 1 September 2015, Page 531.

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