How to decide the best diet for weight loss (and avoid bad ones)

Which diet is best for weight loss? is one of the most-asked health questions, and the answer is surprisingly straightforward: it doesn't matter.

You're likely to lose weight on any diet that creates an energy deficit — that is, one where you consume less energy (from food and drink) than you used through physical activity.

There's no magic secret to keto, or paleo, or intermittent fasting, or any other popular diet. They all work in the short term because they restrict total energy intake. You could eat nothing but burgers, pizza and chocolate and lose weight, if the energy in all that junk food stayed less than the energy you burned through activity.

Which proves that .

That's because most diets impose punishing rules and restrictions that you can stick to for a few weeks, or months (resulting in fast weight loss)... until they become unsustainable and you fall back into your old eating habits (resulting in faster weight gain).

"If you're drinking liquids all day every day or starving yourself a couple of days a week or only eating certain foods that are hard to find … it's impossible to stick to," warns Demaio. "You need to find a diet that is sustainable long term."

He suggests a few questions to test your new diet's sustainability. First: can you build it into your lifestyle, without having to make dramatic changes to your daily schedule?

"It's really finding something that's easy to do, that's affordable to do," Demaio says, suggesting simple diet changes to start out such as reducing portion sizes and making vegetables the "hero" of every meal.

"I try to pack in the vegetables as much as possible — but I pack in the veg I love," he says. "Don't force yourself to eat things you don't enjoy."

Second, will you lose weight on this diet fast or slow? It's not what you want to hear, but slower is better: Though everyone wants to drop as much weight as fast as possible, rapid weight loss sparks changes in the body that increase the odds of it all returning.

"We know from research that if you lose a lot of weight really quickly that you get a hormonal response and your body thinks you're starving," Demaio explains. "You end up putting the weight back on and then more."

Third, and perhaps most important, is asking whether this diet tastes good — will you actually look forward to flavoursome and satisfying food, or will you dread every meal (which in turn makes it likely you'll binge on junk)?

"Food is such an important part of life," Demaio tells Coach. "I'm from an Italian family — I love food. I love pasta and a delicious dinner with a lot of wine.

"So the idea of giving it all up and only drinking smoothies for the next five years, it's not possible and it's not good for you."

Ultimately, losing weight is less about going on a short-term, unsustainable diet and more about finding a way of eating you can live by for months, years and even decades.

"Find something you enjoy that allows you to still eat the foods you love, but in a way that's integrated into a balanced, healthy diet," Demaio concludes.

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