Britney Spears is looking good.

Not only has her hair grown back, but she has slimmed down, too. (I don't think Britney was overweight, but you have to admit she did look pretty unhealthy during her series of personal crises over the last couple of years.)

On the cover of OK! Magazine, a tanned, bikini-clad Spears reveals her toned new bod.

Spears' plan

"I'm the healthiest I've been all my life," Britney, 26, tells OK!. "My diet has a lot to do with my getting into shape. I have no sugar. I don't eat fruit or even fruit juice because of the sugar. I eat chicken and salmon and rice. I eat avocados. I'll have egg whites for breakfast and sometimes turkey burgers for lunch. I try to do just 1,200 calories a day. It may sound like it's not much, but it's actually a lot of food if you eat the right things."

Of course, Brit also hits the gym on a regular basis, doing "lots of cardio and weights" five days a week.

While Britney certainly looks happier and healthier than we've seen her in a long time, take a closer look at that nutrition and exercise regime.

The dailySpark's Celebrity Diet Lowdown

Protein boost Getting enough protein is important, according to experts. Protein helps you stay fuller longer. (That's why experts say to include protein at every meal, because it takes longer to digest and helps keep you from feeling hungry right away.) After a workout, eating protein will stop your body from breaking down muscle tissue for energy and initiate the process of rebuilding and repairing your muscles.

SparkPeople recommends that 10% to 35% of calories should come from protein, which means the remaining 65% or more of your calories should come from the other food groups.

Vetoing sugar In the past, 26-year-old Spears was often photographed with oversized, calorie-laden, frozen coffee creations topped with chocolate and whipped cream. Cutting those regular indulgences (along with other processed foods) surely makes an impact on the waistline. But Britney's plan treats all sugars as equal and excludes fruit and fruit juice.

Fruit contains sugar, yes, but it is a naturally occurring sugar that is packed with nutrients. And not all fruit is high in carbs and sugar. Strawberries, raspberries and blueberries are at the low end of the spectrum of carbs in fruit. (They're full of antioxidants, phytonutrients and fiber to boot!)

Just 1,200 calories? Spears, a mother of two active young boys, is only eating 1,200 calories or so a day, and she's working out five days a week. I'm guessing she's hungry. Really, really hungry.

SparkPeople doesn't recommend that any female eat fewer than 1,200 calories daily or that any male eat fewer than 1,500 calories daily.

When calories drop too low (usually below 1,200 calories for women and 1,500 calories for men), your body’s protection mechanism switches on because the body thinks it is starving. In order to conserve energy, the body lowers your metabolism and you will not burn calories as quickly. This results in a slower weight loss rate or sometimes prohibits any weight loss from occurring.

At SparkPeople, our experts call this “Starvation Mode.” When your caloric intake falls below these levels, it is also extremely difficult to obtain all the nutrients that your body needs for health and survival. These very low calorie intakes can also lead to other health problems such as eating disorders, gout, gallstones, and heart complications.

Verdict

Spears' diet excludes entire food groups and keeps her calories pretty low. Do you think she'll keep the weight off? Time will tell, and she seems determined. Let's hope she listens to the secrets of the 5%.

Photo: OK! Magazine