Twin Doctors Go Low-Fat Vs. Low-Carb to Find Out What Really Works

And the winner is...

If you’ve been waging a lifelong battle for a healthy weight and fitness level (so basically, if you’re like any of us), you’ve probably gotten pretty used to encountering people with — shall we say — creative differences in their beliefs about what works best. Some folks are all about the low-fat approach, and others swear by low-carb eating. (And it doesn’t help that the media vacillates almost daily on the science behind each strategy.)

Well, one pair of doctors found a pretty much unassailable way of testing out what works and what doesn’t: Identical twins Alexander and Chris Van Tulleken, who are each 35 and medical professionals, set out to go on different diets for a month. In the experiment they conducted for BBC's Horizon as cited in the Daily Mail, Chris cut out fat almost entirely, and Alex did the same with carbs, and by extension, sugar. Each could eat as much in volume as he wanted, and each kept his exercise level consistent with the other’s.


First of all, both guys found the experiment very tough. Writing in the Mail, Alex said, "Let me tell you straight up that both of these diets were miserable. I thought I'd got the better deal: I could eat meat, fish, eggs and cheese. But take away carbohydrates and the joy goes out of meals. And remove all fruit and veg — they all have carbs — and you get constipated. Though I was never hungry, I felt slow and tired, and my breath was terrible. Chris on his low-fat diet didn't fare much better. He never felt full, so was constantly snacking, and like me he found that all the pleasure had gone out of meals.”

During the process, Alex — the low-carb twin — found he was losing more weight. But he also noted that his performance in life, both physical and mental, was suffering. His body was getting some energy from the protein he consumed, but it was also breaking down his own muscle. Chris — the low-fat twin — also lost weight, "but over the long term, unregulated consumption of sugar may also have negative health consequences.” Meaning, carbs without fat may actually be dangerous in the long run.


In the end, the most important takeaway the guys reported is that neither diet felt particularly sustainable — and lifelong sustainability is the key to a healthy diet.


Moreover, it’s not that carbs and sugar or fat can definitively be considered a bigger culprit in our weight battles: It’s the combination of the two categories — which has a similar effect on the brain to cocaine, according to scientists cited in the Mail report -- that's so problematic.

Writing in the Mail, Alex concluded, "If you want to lose weight it will be much easier if you avoid processed foods made with sugar and fat. These foods affect your brain in a completely different way from natural foods and it's hard for anyone to resist eating too much.”


So according to the twins’ experiment, what it comes down to — as usual — is moderation. If we enjoy carbs and fats in a regulated manner — but ditch the bagged snack mix and Chips Ahoy — we stand a better chance at staying fit and trim over the long term than any other more extreme approach.

Logical, yes. Easy? Never.


What’s your personal diet strategy?

Alesandra Dubin is a Los Angeles-based writer and the founder of home and travel blog Homebody in Motion. Follow her on FacebookGoogle+ and Twitter.

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