These are the best diets to lose weight, get in shape, and eat healthier

Weight Watchers has been around for years, but now that Oprah is behind it, the diet has again spiked in popularity.

The diet, which claims you can lose up to two pounds a week (a safe amount, according to the UK's National Health Service) operates on a SmartPoints system that supports choosing healthier foods that will fill you up (think protein and fiber) over foods that are lower in nutritional value.

Weight Watchers puts no restriction on what you can eat and is flexible for those with dietary restrictions, but the point-counting process can be tedious and the program can cost anywhere from about $20-$70 a month.

The Health Management Resources program (HMR) tied with the Biggest Loser diet for the best rapid weight-loss diet.

HMR depends on meal-replacement shakes, bars, and cereals for weight loss. Experts say that meal replacements lead to three times as much weight loss compared to traditional diets. Meals are delivered to you, which is another pro; however, shakes and bars can become bland after a while, and the diet makes it difficult to go out to eat.

The Biggest Loser diet, based on the reality TV show of the same name, drills in the importance of exercise as a companion to a healthy diet. The diet emphasizes portion control with nutritionally dense foods and getting "up off the sofa." It's a lot of work and a bit expensive, but it's effective and offers no restrictions on the foods you can eat.

"DASH" stands for Dietary Approaches to Stop Hypertension, and the plan involves lowering sodium intake to prevent and lower high blood pressure, which, if left untreated, can cause heart and kidney disease, stroke, and blindness.

DASH was not developed for weight loss and can be more work-intensive and a bit pricier than other diets, since it emphasizes fresh groceries, but it's heart-healthy and nutritionally sound.

The DASH diet recommends working down to a maximum sodium intake of 1,500 mg a day (the FDA daily recommendation is less than 2,400 mg) and eating fresh produce, lean protein, whole grains, and low-fat dairy.

The Fertility diet was originally created by two Harvard doctors for, you guessed it, fertility — the diet claims to boost ovulation and improve fertility in females through increased consumption of "good" (monounsaturated, polyunsaturated) fats, whole grains, and plant proteins, and decreased consumption of "bad" (saturated) fats, refined carbs, and red meat. The diet is proven to help those with irregular ovulation, but this is the cause of infertility in fewer than a third of women who have trouble conceiving.

The decreased intake of some of these foods, particularly refined carbs, is what makes the diet also work particularly well for diabetics who have to control their blood sugar levels. The diet is healthy and balanced but is recommended only for women.

Weight Watchers tied with the Fertility diet and MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) for the easiest-to-follow diet.

Research at Rush University Medical Center funded by the National Institute on Aging found that balancing the Mediterranean diet with the DASH diet can lower the risk of developing Alzheimer's by as much as 53%; it could also slow mental decline in Parkinson's or other neurodegenerative diseases.

MIND follows a food regimen of 10 brain-healthy food groups: green leafy vegetables in particular, other vegetables, nuts, berries, beans, whole grains, fish, poultry, olive oil and, yes, wine. This is an easy diet to follow, but because the research is new there isn't much information available yet.

Outlined in Dean Ornish's 2007 book "The Spectrum," the Ornish diet categorized food into five groups from the most healthy (group 1) to the least healthy (group 5).

Dr. Ornish is a professor of medicine at the University of California at San Francisco and founder of the Preventive Medicine Research Institute in Sausalito.

His diet is flexible and allegedly can be tailored to help you lose weight, prevent diabetes or heart disease, lower blood pressure and cholesterol, and help prevent prostate or breast cancer. But whole grains, fresh produce, and lean protein — staples the diet promotes — are expensive, and the program can be difficult to follow in the long-term.

Weight Watchers tied with the Mayo Clinic diet — a new addition to US News' list — for the best commercial diet. The Mayo Clinic diet was developed by the Minnesota-based medical research group as a sustainable weight-loss program. The diet says you'll shed anywhere from six to 10 pounds in the first two weeks, and another pound or two every week thereafter.

Through whole ingredients like grains, fruits, vegetables, lean protein, and healthy fats, the Mayo Clinic diet helps you recalibrate your habits in a healthy way. It's not an easy regimen to follow, as 30 minutes or more of exercise a day is required and rules include no sugar, no eating in front of the TV, and no snacking (except on fruits and veggies), but it's certainly an effective diet.

The Mediterranean diet has worked for many people and is great for vegetarians or those whose diets are already plant-heavy. High in fresh produce (obviously) as well as healthy fats, like the ones found in nuts and olive oil, the diet is good for your brain and heart and may help keep a number of chronic illnesses at bay.

It's not the best diet for your wallet — these ingredients are expensive — and it suggests staying away from red meat, sugar, and saturated fat, but those who follow it lose weight, and keep it off.

US News also rated the DASH diet as the best diet overall, as well as the best diet for healthy eating.

It ranked No. 2 for best diets for diabetics and No. 3 for best heart-healthy diets; it's easy to follow, and it's also not a cold-turkey diet: Experts say it's okay to ease into the DASH diet by slowly reducing sodium intake, adding an extra serving of fruit or veggies here and there, and going meat-free one or two meals a week.

Developed with the help of the National Heart, Lung, and Blood Institute (NHLBI), DASH can be tailored for weight loss through portion control and moderate exercise.