4 The 17-day Diet
Here's the skinny: This diet has become a fast internet sensation, and it looks set to get bigger.
Dr Mike Moreno has devised a "simple plan that targets both belly fat and visceral fat and produces fast results that last".
A diet that can shift your spare tyre in a little over two weeks? Too good to be true?
Get your teeth into it
The 17-day period is just the first stage of the four-phase diet. The plan kicks off with an 'Accelerate' step -- a low-carb diet that provides around 1,200 calories a day.
You can eat all the lean meat and no-starch veggies you like, along with two fat-free plain yogurts and two low-sugar fruits.
This phase is followed by 'Activate', from day 18 until day 34, which involves changing your calorie intake from low to high over several days in an effort to 'trick' your metabolism, then starting again.
With two servings of wholegrains also on the menu, the average daily intake is 1,500 calories a day.
Now it's time to 'Achieve', from day 35 until day 51. Lean meat is no longer unlimited, but more grains and fruit are added -- plus you have the option of a serving of alcohol, and a 100-calorie snack.
From day 52 onwards, it's time for 'Arrive'. You spend your weekdays cycling through the first three stages, then on the weekends you are allow to splurge. But gain more than five pounds and you have to go back to the 'Activate' stage.
Why you should try it
If you enjoy perky inspiration, you're in for a treat: "We've all pledged, promised and bullied ourselves to eat better and exercise more, but so many times even the best intentions fall short. I incorporate healthy habits into my work and home life and you can too."
Why you shouldn't
Dr Mike is the first to admit that it's not appropriate for type 1 diabetics, teens, pregnant and lactating women, or anyone who's ill. Plus the first two phases are pretty hardcore, so you might be wise to take a multivitamin-mineral supplement.
The jury's out on what shortcuts you can take to 'trick' your body's systems.
"There is no harm in calorie cycling temporarily or indefinitely and the process happens naturally for most people, who don't eat or burn the same number of calories every day.
"But I'm not in favour of focusing on any process that takes you away from attending to the lifestyle changes you need to make and practice for permanent weight control," says Mary Hartley, RD, MPH, and director of nutrition at Calorie Count.