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Diet. The most emotion-packed four-letter-word in our vocabulary. We’ve all been on one. We’ve all failed on one—some of us, several times.

Here is what we know. We are getting heavier. Alarmingly so. New federal data shows 40 percent of Americans are obese. Forty percent. «You?» That’s a sharp 10 percent increase over the last decade.

During that same time period, we saw people who fall into the severely obese category jump from around 6 percent to nearly 8 percent.

The findings from the National Health and Nutrition Examination Survey show efforts to educate people about the dangers of obesity are largely falling on deaf ears. Or, they are falling on ears that are too tired and too overworked to listen.

Losing weight is hard. Keeping weight off is even harder. Diet companies know this and continue to spin their wheels, selling everything from exorbitantly priced, pre-packaged meals to highly caffeinated pills masquerading as guaranteed weight loss boosters.

This is big business.

It’s one of the biggest profit-making industries in the world. A report by the Market Research Engine predicts weight loss products will top $253 billion worldwide within the next four years. In the U.S. alone, the weight loss market is expected to hit the $70 billion mark by the end of this year.

There is good news. Millennials now outnumber baby boomers, and they tend to lean toward inexpensive, convenient diet plans. More importantly, they’re focusing on lifestyle changes that work—clean eating, exercise, and avoiding processed foods.

The main thing to remember is there is no one diet that works for the entire population.

Each of us is different, and different plans work for different people. Luckily, technology is dramatically increasing our understanding of how our bodies work, and with with technological breakthroughs come eating lifestyles for nearly everyone.

Let’s break it down.

Mediterranean

The Mediterranean diet is perhaps  the most studied, long-term weight loss program that consistently shows healthy, sustainable results. It also tied this year for best overall diet as ranked by U.S. News and World Report. (The DASH diet also came in first. It’s a similar plan that was specifically created to lower hypertension.)

The Plan: Eating lots of fresh fruits and vegetables, whole grains, beans, nuts, and healthy fats like olive oil. Seafood should be eaten a couple times a week. Poultry, eggs, cheese, and yogurt are eaten in moderation. Red meat is saved for special occasions. Top it all off with a glass of wine with dinner, and you’re set.

Who Benefits: Anyone looking for proven heart-healthy results. This is also great if you enjoy variety, and studies show people often stick to this eating program longer than other ones.

Who May Struggle: Anyone who needs more structure. The Mediterranean diet doesn’t come with a “one-size-fits-all” manual. It’s up to you to decide how many calories to eat and how to count them. It’s also up to you to come up with daily eating plans.

What People Are Saying: “I make a big bag of shredded cabbage on Sunday; then during the week I add different proteins, nuts, and dressings for dinner. It’s as easy or as hard as you make it,” said Tammy Torche, a 50-year-old office worker who’s been eating Mediterranean for 10 years and has lost 40 pounds.

Pre-Packaged Foods

These may be among the easiest (and most expensive) diets to follow. In the list of overall top eating plans for 2018, Jenny Craig came in 12th, Nutrisystem in 19th, and Medifast in 29th. These are just some of the companies that send pre-packaged food, shakes, and protein bars right to your door. In addition, you usually need to buy supplemental foods like fresh fruits and vegetables.

The Plans: Usually these diets work in two phases. The first step is to lose weight. The second is to shift back to regular eating. On Jenny Craig, all food is pre-packaged until you’re halfway to your goal weight. Then you begin cooking for yourself twice a week. Once at goal, you transition to making all your own meals. Nutrisystem also provides you with pre-made meals that transition to regular eating. Medifast does a 5-1 plan. Eat five pre-packaged meals, then make one meal yourself.

Who Benefits: Anyone who doesn’t want to count calories. These diets are super easy and don’t require a lot of thought. Just add water and microwave (many don’t even require water). The hardest part is deciding between beef stew or pasta.

Who May Struggle: Anyone on a budget. These plans range from around $330 a month for Medifast and Nutrisystem to more than $600 a month for Jenny Craig. And that’s just for the basic food. You’ll need to budget money for extra food bought at the grocery store and for any enrollment and monthly fees. This also may not be the best plan for foodies or people who enjoy cooking.

Weight Watchers

An oldie and a goody. This program ranked fourth overall, but in the fast weight loss and commercial weight loss categories, it scored first place.

The Plan: Weight Watchers replaces calories with points. Nutritional values dominate the rating system. That is why a 100-calorie apple is zero points, while 100 calories worth of potato chips will quickly add up. How many points you get to “spend” each day depends on factors like weight and gender. Exercise can also be used to earn extra points.

Technically, you can eat whatever you want if you stay within your points. But, with zero-point foods like skinless chicken, fish, and eggs, it’s easy to see how it gently pushes people toward healthier eating. The program also offers everything from do-it-yourself internet programs to weekly, in-person group meetings with lessons and support.

Who Benefits: Just about everyone. Because the program is so flexible, you can cater it to your specific needs. This is one reason the plan has been around for so long. If you need extra support, you can attend as many Weight Watchers meetings as necessary.

Who May Struggle: People who have a lot of weight to lose may want to consider other options or modify this plan, as this program is set for a two-pound-per-week loss. For people with a few pounds to lose, it’s a very healthy rate. But, for severely obese people, doctors often recommend something that will drop the pounds faster. You’ll pay around $7-$14 a week, depending on which plan you select.

What People Are Saying: “I like that I do not have to give up my favorite things. I simply must keep moderation in mind,” said Denny Pfeifer, a 51-year-old woman who teaches English as a Second Language to college students.

Vegetarian

The vegetarian lifestyle rounds out the top 10, with vegans pulling in at 19th for best overall diets. Research shows vegetarians tend to eat fewer calories, weigh less, and have a lower body mass index than those who eat meat. This does not, however, mean you will lose weight by only cutting out meat.

The Plan: Simple. Don’t eat meat. Actually, it’s far from simple if you want to be healthy. Most vegetarians choose the lacto-ovo approach turning their backs on meat, fish, and poultry, but still eating dairy products and eggs. Vegans shun all animal products. It’s important to make sure you get enough protein by adding beans and whole grains to your diet.

Who Benefits: Anyone who loves animals. Documentaries on how farm animals are raised and killed is enough to turn many people into vegetarians. Others do it for the health benefits. It’s also a good plan for people on a budget. Even though fresh fruits and vegetables can be expensive, meat is often the high-ticket item at the grocery stores. People with heart disease and diabetes can also benefit from a vegetarian lifestyle.

Who May Struggle: Anyone who likes a good steak. If you can’t take the turkey out of Thanksgiving, chances are this meal plan is not for you. It also takes a lot of initial planning. Like most programs, it gets easier the more you do it. But, at first, it’s important to measure daily protein grams to make sure you’re getting enough.

What People Are Saying: “I can be an example … and tell my story about how eating plant-based foods made me better and made me feel better too,” said 24-year-old Vivian Kong Man-wai, the world’s ninth-ranked fencer, who turned to a vegan diet after she suffered a knee injury. She told the South China Morning Post eating vegetarian not only sped up her recovery, but helped her improve her game.

Medical Weight Loss

By the end of this year, medical weight loss programs, including bariatric surgery, will make up an estimated $7.6 billion market. The increase in medical weight loss is being driven by two factors: the increasing number of severely obese Americans and research showing bariatric surgery may be the only true long-term way for super-obese people to get their weight under control.

The Plans: Bariatric surgeries are more popular than ever. The gastric sleeve is the fastest-growing operation where surgeons remove about 80 percent of your stomach. Gastric bypass also severely reduces stomach size while re-working your intestines so you’ll absorb less calories.

The gastric band involves having a band inserted around your stomach that is then filled with fluid to restrict stomach size. This is decreasing in popularity, as many bands slip and need to be removed. Finally, the gastric balloon is a newer approach to temporary weight loss. A balloon is inflated inside the stomach, making it smaller. Eventually, the balloon is deflated, and the stomach goes back to its regular size.

Who Benefits: People who have 100 pounds or more to lose or people who are overweight and suffer from obesity-related comorbidities like diabetes, sleep apnea, or heart disease. Weight loss surgery is a serious approach for extreme cases. Many say these surgeries saved their lives.

Who May Struggle: People who do not have an extraordinary amount of weight to lose. Weight loss surgery is far from easy. It involves weeks of no solid food, then years of eating less than a half cup of food at a time. It also may not be for people with medical conditions that could put them at risk. Often doctors and patients weigh the medical risks of surgery against the medical risks of being morbidly obese.

What People Are Saying: “For the first time in my entire life, I feel like I’m living. This surgery not only saved my life, it gave me back my life. I can fit in airplane seats and roller coasters. And I can finally keep up with my kids,” said Alita Jones, a 33-year-old mother of two.

Keto

Keto ranked dead-last on the U.S. News and World Report’s 2018 diet rankings. For people who follow the eating plan, this may not be surprising. Keto can be controversial and is often misunderstood. It turns the traditional food pyramid on its head. Fat is on top; carbs are on the bottom. With Keto dominating best-selling book charts and the popular Netflix documentary, The Magic Pill, this is a diet that’s catching fire. Fast.

It’s potential to eradicate some common illnesses, depression, and anxiety drives a lot of followers. Since the 1920s, some people have even used it to prevent seizures.

The Plan: The idea is to put the body into a state of ketosis where it burns fat instead of carbs. Sugar is a no-no. A strict no-no. So are grains. The plan is about 70 percent healthy fats, 5 percent carbs, and 25 percent protein. When only fat is available for the body to burn, the body converts the fats into fatty acids, and then into compounds called ketones, which can be taken up and used to fuel the body’s cells. The more fat you burn, the more weight you lose.

There are dozens of apps you can use to help calculate how many calories, carbs, proteins, and fats your body needs a day to successfully lose weight. It is important to note, long-term studies on Keto are still coming in. And a recent study shows you may do better to lean toward a lot of plant-based fats like avocados and olive oils instead of relying heavily on animal fats.

Who Benefits: People who have a lot of weight to lose. This plan dramatically cuts cravings, so it’s easier to stick to, once you get past the first few weeks (those can be hard, given sugar withdrawals and your body changing how it burns energy). Some doctors are recommending this eating plan for people with cancer, sugar-level challenges, and/or people with chronic immune disorders. By eliminating sugars and grains, you’re also eliminating foods that fuel cancer cells and cause internal inflammation. (Note: there is no definitive proof Keto cures or prevents cancer.)

Who May Struggle: Many people with diabetes use Keto to control their sugar levels. But, always check with your doctor first, because going into ketosis with some types of diabetes can be dangerous. People who need quick and easy plans may struggle with this at first. It’s challenging to learn how to cook without wheat-based flour and sugar. Meal planning is a must.

What People Are Saying: “I have tried so many plans, and I’m happiest with this lifestyle, and I’m finally seeing results while not being overly strict and being deprived,” said Rosa Loaiza, a woman in her 20s who said she’s not only lost weight, she’s resolved several health issues like heartburn and psoriasis.

Whatever approach you take, the possibilities are endless. Just remember the basics. Good nutrition, adequate sleep, and exercise are the only healthy and sustainable ways to lose weight and keep it off.