I grew up in rural PEI (yes, I know that is a redundant statement.)

When I was about 11 or 12 one of my chores was to mow our 4 acre property and a real love-hate relationship was quickly born.

Hate because it took forever, involved 7-8hrs of push-mowing and the mosquitoes were fierce. Love because it meant I got to drive the ride-on lawnmower – a big Kubota tractor with an industrial mower attached that could turn anything to mulch.  A real country boy toy…

Now the biggest thing to remember is that the tractor had a diesel engine.  It wasn’t hard to miss – ‘Diesel’ was written on the tank, the cap and on all the appropriate jerry cans.

But when you’re 12, who reads that stuff?  So one day I noticed it needed refuelling and, well you can see where this is going…

Have you ever put gas in a diesel engine?

Or better yet, have you ever had to siphon the resulting gasoline/diesel mix from the tank by mouth?? (my dad’s idea of character building…)

Here’s the take home points:

One, a diesel engine will work for a little while but not very efficiently and the gas will eventually cause serious damage to the engine parts.  Not good.

And two, repeated attempts to siphon fuel from a tank will make you feel pretty dizzy, tastes disgusting and has the added benefit of killing off a bunch of brain cells.

Needless to say, I learned a very valuable lesson that day:  always put the right fuel in to match the engine.
It turns out this principle is true for all engines: An engine will alway run best on the fuel it is designed for.

Little Tiny Human Engines

Did you know that your body has trillions of little engines?

Almost every one of your 30-50 trillion cells in your body is powered by engines called ‘mitochondria.’  These little powerhouses turn the fuel that we extract from our food (fat, carbohydrate and even protein) and turn it into energy so that our cells can do what they are designed to do.

While all your cells have mitochondria (except red blood cells for you fellow nerds), some cells have more than others to match the amount of energy they require.  For example your brain cells have way more mitochondria than your bone cells. (No surprise that your muscle cells have the most of any cell)
  And like all engines, your mitochondria function best when given the right fuel.

Sugar Burner

You’re probably thinking – “obviously we all know our cells burn sugar” (or if you’re fancy – glucose), that’s why you have to carb-load the night before the big game or guzzle sugar-laden energy drinks during your treadmill marathon…

Let’s keep it simple (with the caveat that mitochondrial function is pretty complex) and consider all your mitochondria as functioning the same.  Yes, they can and will burn sugar – and the more readily available sugar is, the more adapted they become to burning sugar.

But that comes at a pretty serious cost:

For one thing, your body can only store a small amount of sugar (glucose) in your liver and muscles and when our mitochondria are preset to burn glucose you are constantly in need for more of it.  If you crave sugar morning, afternoon and at bedtime it likely means you’re a sugar burner and are dependent on sugar as fuel.

An important side note: when you’re a sugar burner your brain is constantly getting signals to eat more sugar – but if we don’t use up that sugar (say during exercise) then it needs to be stored somewhere.  Guess where?  Yep – Excess sugar gets converted into fatty acids by the liver and deposited in the tissues – typically around the midsection.

“But I thought Fat made me Fat?” One of the many myths we have swallowed hook, line and sinker.   It’s actually an overconsumption of carbs that make us fat, but that’s another post…

Second, it turns out  sugar – to your little engines – is like gas to my Kubota diesel:  it works… but way less efficiently and causes a lot of damage.

I’ll save you the details, but essentially relying on burning sugar causes your mitochondria to make way more free radicals and these wear down the mitochondria making them even less efficient. Not to mention free radicals cause genetic damage and are strongly linked to almost all forms of cancer.

Let’s be clear,  your cells ARE designed to burn sugar – in fact it’s a super important fuel source under certain circumstances (like during high intensity exercise) – but it’s not the best fuel most of the time.

And because we can only store a small amount of it, wouldn’t you rather save it for when you kick it into high gear?

So what’s the ideal fuel source for your human engines?

Fat = Diesel

That’s right, as a human being your body is genetically hard-wired to work best as a fat burner. Just like my Kubota was perfectly designed to burn diesel, our mitochondria burn fatty acids much more cleanly (think bio-diesel) with far less wear and tear on your little engines and less free radical production. Why is that?

It really comes down to what our ancestors did for the bulk of history,  when fat and protein in the form of healthy animal sources made up a significant part of our food supply, our bodies became really good at burning fat and using protein.

It’s only the past few hundred years that we’ve watched that change dramatically.  And our health has followed suit and plummeted to a frightening place in which 30% of Canadians are considered obese. The good news – we have plenty of fat available for energy. The bad news – you’re just not well adapted to using it yet.

Let’s get fat-adapted!

The cool thing is your body is an amazing adapting machine and you can get your body  back to its By Design, ‘fat burner’ state simply by making a few changes.

What’s exciting about this switch is there is better use of stored fat as your fuel (which means FAT LOSS) and improved blood sugar regulation as your body no longer requires sugar as its main fuel source.  All this translates to better sleep, more available energy, better focus and hundreds of other known effects.

How do you do it?

Eat By Design! (Click HERE to register for the next Eat By Design seminar.)

The first week or two can be tough as your body adjusts to this new way of eating and your brain wraps itself around going without all those sweet tastes and sugar-driven energy spikes. Switching from burning sugar as your main fuel source to fat (keto-adaptation) can take several weeks so it’s important you stick to your plan.


During this time you may not feel great, just like an alcoholic doesn’t feel great in those first few weeks of rehab. Trust your body and support it by staying focused on animal sources of protein and plenty of good fats along with your fruits and veggies.

And if the going gets tough, just remember those little engines purring along and know that you’re making a change that will help you live a longer, healthier, happier life!

Dr. John MacPhee is a Chiropractor, speaker and passionate  health  and wellness expert.  He has inspired thousands of people to take control of their own health using the Life By Design method.   Dr. John is co-owner of The Wellness Group, the largest Life By Design Certified Chiropractic office in Canada. Apart from full time practice, John maintains a busy speaking schedule, with a particular emphasis on improving productivity and focus at work.  Otherwise you can find John training hard at CrossFit 613, exploring Gatineau Park, or holed away studying the latest research at various cafes across the west end.