Low fat, or low carbs? Which is best?

  • Clive
  • 08/11/2013 12:25 pm
  • Diet

Welcome to the first in a series of two articles that aim to help people improve their understanding of nutrition and the way our bodies process food – thus helping them to develop a healthy and enjoyable relationship with food.
Here, Clive Reader, co-founder of YOU FOOD, looks at the science behind the often contradictory advice about healthy eating.

Steak and vegetables

I was alerted to the latest nutritional theories, which overturn decades of advice about achieving weight loss, by a long-time friend of mine (Adrian) who came across the science that I am about to tell you about.  Having a scientific background like me, Adrian became fascinated, and looked into it in a lot more detail.

As a slightly overweight middle-aged man, who had been unable to exercise for a while due to a skiing injury, he needed to start monitoring his food intake.  So he fully researched the subject and tried out the theory for himself. It achieved all that was predicted: the weight fell off of him!

What you are about to read is revolutionary.  It is proven by science, and proven by real life examples.  If you are overweight and want to change your life and become a thinner person, this will show you how.  If you don’t, that’s fine too – but you ought to know why you are not thin, and how you could become thin if you wanted to be.

So why is this revolutionary?

Let’s start with a basic equation that we have all heard, which sounds as though it must be true: calories in minus calories out = fat stored on your body.  In other words, if you take in more calories than you expend, you will get fat.  By implication also, if you burn more calories than you take in, you will lose weight.  “Exercise to lose weight!”  It obeys the law of conservation of energy, so it must be true, right?  Wrong.  It is wrong because it is too simple.  Some of the terms of the equation are missing.

You see, there are “good” calories, and “bad” calories.  Some calories are in a form that the body turns straight into fat and stores on your body.  Other calories get burned up instantly in the right circumstances, so don’t make you fat.  So which are which?

Fruit juice

(Q) Good or bad? …….(A) Bad: too much sugar!

Well, we’ve all heard of low-fat diets – low-fat foods are a multi-billion pound industry.  Eating fat makes you fat – obvious, yes?  It sounds obvious, but it’s not necessarily true.  Fat and carbohydrates provide flavour to food in various ways.  If you remove fat from food, it can become bland and tasteless, so a manufacturer of low-fat food products might put more carbohydrates in to improve the flavour.

So, which are the “good” and “bad” calories?  Here’s the surprise: fats are good, carbohydrates are bad!  Eating fat doesn’t make you fat necessarily!  Eating carbohydrates makes you fat.

It’s not entirely that simple, of course, and this series of blogs will bring you the detailed science from the experts, for those who are interested in that level of detail.  But don’t expect, any time soon, that the multi-billion pound food manufacturing industry is going to abandon low-fat food products, and replace them with higher fat, low carb products.   It may change slowly over time, but it won’t happen overnight.  For a start, you have to persuade all of those people who you told that “low-fat” was much better for them than higher fat, that now the reverse is true, and low fat does not matter anymore, it’s the carbs that count.  You might even deny the science, and insist that your high-selling, very profitable low-fat food products are better than higher fat, low carb products!

A qualified nutritionist takes up the story and explains more of the science…



Sam Marshall (PgDip, BSc, DipHNP, DipAIT Member FNTP) has her own healthy-eating website called  Well Necessities.  She told YOU FOOD the following:

The truth about fat when dieting…

If you haven’t tried a low fat, low calorie diet yourself, you probably know someone who has.  Although many people do manage to shed some pounds following this kind of plan, more often than not they find the weight back on again – and often with interest.  So why do we continue to believe that these low fat diets work and what was the science behind them in the first place?

The low fat low calorie diet is based on the Law of Thermodynamics1, which works on the principle that if the number of calories going into our bodies, is exceeded by the number of calories we expend every day, then our bodies have to look for internal sources of calories to make up the deficit.  Namely our bodies will burn our own fat.  This is a sound principle in theory, but the body is very good at adapting and eventually takes steps to lower our metabolism, to compensate for the decrease in calories.  More importantly our body actually looks at ways it can conserve fat, as it is so vitally important to our health, so once we start to eat normally again the pounds pile on.Low Fat Food

The reason that fat has been targeted by this thermodynamic approach to weight loss is because fat has over 2 times the calories per gram as carbohydrates.  A low fat approach is an easy win.  This is why general nutritional advice and many of the ‘diet’ products offered by the food industry favour carbohydrate consumption over fat consumption to create a lower calorie diet.

However, fats are actually an essential food source along with proteins.  This means we must have them in our diet for our body to work optimally.  Carbohydrates are not essential, as the human body can meet its glucose needs by metabolising fats or protein into glucose.  Excess glucose in the diet in the form of simple sugars or even starchy carbohydrates (so called healthy carbohydrates like whole grains), create huge problems for our insulin levels and are actually the chief culprit of weight gain, inflammation and increased fat stores along with many other health problems.2

So does eating fat make us fat?

Low Fat Diet cartoonThe simple answer is that eating healthy fats doesn’t make you fat, but unhealthy fats can.  We think of healthy fats as being those polyunsaturated fats that the media promote as helping to “lower cholesterol”.  However, the truth is more complex.  Healthy fats are really ones that the body can use cleanly and efficiently, be they saturated or unsaturated3.

Saturated fat is actually a vital food source for a healthy body and is essential for all hormone production and for keeping your organs (like your liver and brain) healthy.  It is also a stable energy source.  Healthy saturated fat would ideally come from animals that have been allowed to live “free range” or organically, eating grass and natural foliage and without the routine use of antibiotics and hormones.  Examples would be duck fat, chicken fat, beef tallow, organic lard, eggs, butter, ghee, cheese and cream.   Other “healthy” fats are fish oils (from wild fish), fermented cod liver oil, avocados, coconuts, olives, nuts and seeds.

These fats can become unhealthy in two ways.  With animal and fish fats, the quality of the fat depends on how well the animal was kept in life.  If animal or fish were battery farmed and fed on grains, their fat contains higher levels of omega 6 than omega 3 and this can be very inflammatory for our bodies and actually have a negative impact on our appetite encouraging us to over-eat.  The toxic by-products from antibiotics and hormones supplementation are also stored in the fat, so we then ingest this too.

For the vegetable fats like nut and seed oils, when they are heated the fragile bonds between the fats are broken, meaning that our body cannot use them as we need, for example in cellular membrane communication.  These fats are best consumed cold i.e. in salad dressings4.


Saturated fats are stable to much higher cooking temperatures so it is actually best to use moderate amounts of healthy saturated fat e.g. coconut oil, ghee, free range duck fat, organic lard to cook our food.    Science has also found new ways to make unsaturated fats super unhealthy, and this is by turning them into Transfats.  To increase their shelf life (as I mentioned these fats tend to be fragile) they bioengineer them to have a molecular structure similar to saturated fats.  The problem is they do not do the job of saturated fats in the body, but they do block the action of real saturated fats leading to numerous serious health problems2.

So eating healthy fat doesn’t MAKE you fat, however adding even healthy fats to a diet high in carbohydrates (especially sugars) will still negatively impact our weight, as the flood of sugar will inhibit the proper action of fats in the body as a viable energy source.  Excess sugars also Glycate fats: basically, they bind with them making them unusable by the body2.


1. Sean Croxton (2011) The Dark Side of Fat Loss ebook available http://darksideoffatloss.com/

2. Nora T Gedgaudas (2011) Primal Body, Primal Mind; Beyond the Paleo Diet for Total Health and a Longer Life, Healing Arts Press.

3. Dr Natasha Campbell McBride MD (2007) Put Your Heart in Your Mouth, Medinform Publishing.

4. Paul Chek (2004) How to Eat, Move and be Healthy, C.H.E.K Institute LLC.

That’s all for this blog…

In the next blog, Sam will tell you much more detail about the good fats and the bad fats, and have a brief look at some low carb diets.

Peter Attia

Peter Attia

In the mean time, I want to also introduce you to Peter Attia, an American surgeon who did more exercise than most (3 to 4 hours per day), but found that he was still “not thin”, and set himself the challenge of finding out why.  He has written an enormous amount of material, but I suggest that you start on this page of his website by way of introduction, and then explore further, as your interest takes you.

By now, you won’t be surprised to read that what he discovered was exactly what you have been reading about in this blog.  He was fat because he ate too many carbs.    He is now on a super-low-carb diet, and is thin.  His fat intake has increased from 14% of his total intake of calories to 88%, and his carb intake has decreased from 64% of his diet to just 3%.  He exercises less than he used to (2 to 3 hours a day), but he’s now much thinner, despite consuming 4000 to 4500 calories a day!   Now, I’m not advocating that you copy him (it’s entirely your choice), as, being a YOU FOODIE you probably enjoy a wide range of foods and would not be happy on a very limited diet, as most of the things you enjoy will contain carbs – but it is very interesting to read his story!

Adrian, the friend of mine I told you about at the start of this blog, has not been anywhere near as extreme in his diet as Peter Attia, but he has cut out most of the carbs from his diet and has lost the weight, finds that he doesn’t have highs and lows of energy, always feeling energetic, rarely feels hungry, and is now a proselytiser for low-carb diets!

To read the second part of this article, click here.

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