[This article originally appeared in Men’s Health magazine]
Tim Noakes’ revival of a 150-year-old high-fat, low-carbohydrate Harvey Banting diet has been roundly condemned by the medical establishment. The controversy has turned Noakes into a best-seller. It’s good PR – but is it good science?
This is what happens on a low-carb, high-fat diet. First, you cut carbs and sugar. There are no complicated food charts or reading labels. You just skip bread and chips and pasta and sodas and pizza. This alone should reduce your daily kilojoule intake by as much as 20 percent.
The increased amount of protein may suppress your appetite further, making you feel full quicker, and will trigger a couple of other recalibrations. You get constipated. Your breath might start to stink.
Dropping carbs forces your body to look for alternative sources of energy – instead of glucose, it targets the glycogen stored in your liver and your muscles. This process makes you lose weight. You may also look and feel less bloated.
At the same time your liver starts breaking down stored fatty acids, producing a by-product known as ketone bodies. Ketosis (the formation of ketones – which are partly responsible for the bad breath) can also act as an appetite suppressant. Your kidneys flush out the high level of ketones in your urine.
Under these conditions it’s possible to lose several kilograms in a matter of days.
So far most of your weight loss is accounted for by body water – what doctors call “diet-induced diuresis”. You’ve peed it out.
Water loss peaks in the first week. Depending on the shape you were in when you started, if you continue to cut out all carbs and focus only on protein and fat (and providing your total energy intake stays below the amount you use) you’ll probably keep on losing weight without much effort – or without ever really feeling hungry.
This is a revelation.
Unlocking your secret body makes you feel like you’ve won something; the lottery and a tax refund and a bequest from a wealthy uncle all at the same time, like those dodgy emails.
Although everyone knows those things are too good to be true, right?
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