According to Powell and her husband and co-author, Chris, the key to weight loss while still getting your carb fix is all down to carb cycling.
Long popular among body builders, the Powells believe this will be the next big dieting fix.
"You get the results of a low-carb diet, but we've got high-carb days in between to help save your metabolism," says Chris.
The three-week carb-cycling diet plan outlined in their new book calls for four high-carb days, followed by two low-carb days and then a seventh "cheat day."
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The approach is said to help prevent the metabolic slowdown that's common to low-carb diets, which causes people to pile back on the weight as soon as they eat bread again.
"It's the benefits of a low-carb diet, without crashing your metabolism," says Heidi.
The couple, based in Arizona, used the diet to help contestants on a TV show Extreme Weight Loss. They credit it with helping one contestant drop 91 kilograms.
But before you think the diet means you can indulge in cheesy pizza whenever you like, that's not quite the case.
The carbs should be "real, clean, natural carbohydrates," such as whole grain breads, pasta, legumes and fruit.
With over 119, 000 Instagram posts tagged with #carbcycling, the diet looks to be gaining momentum.
- nzherald.co.nz