With the New Year around the corner, you’re probably prepping your resolutions for 2025. And if you’re anything like me, that probably includes changing up your diet to eat healthier (and we’re gonna stick to it this time, right?). Or maybe you’re just curious — or confused — about all the fad diets you’ve seen valorized on the internet in recent years.

Even popular meal kits and prepared meal-delivery services are getting into the specialized-diet game, offering plans that support a range of perhaps unfamiliar food preferences. What’s the difference between keto and Whole 30? Should you be fasting, intermittently or otherwise? And what does it mean for a diet to be “Mediterranean”?

I spoke with Registered Dietitian Nutritionist Caroline Susie, a spokesperson for the Academy of Nutrition and Dietetics, to understand the main benefits (and drawbacks) of 9 popular diets and to find out what makes each of them such a draw.

Mediterranean diet

Low-risk and full of variety, the Mediterranean focuses on plant-based foods and healthy fats, and even allows you to enjoy an occasional glass of red wine with meals (I like it already!). If you’re aiming for a healthier lifestyle, this could be the one for you: It’s anti-inflammatory and it can help with weight management and improve heart and brain function too.

Need a shopping list? When it comes to vegetables, Susie says you should aim for a variety of leafy greens, tomatoes, peppers, eggplant and zucchini. For fruits, opt for fresh options like berries, oranges, apples and figs. Whole grains are also important for this regimen, so stick to wheat bread, brown rice, quinoa, farro and barley — unfortunately, you’ll have to give up French bread. Of course, legumes and nuts are a staple food of the Mediterranean diet, so stock up on chickpeas, lentils, beans, almonds, walnuts and pistachios. Also grab fresh herbs like basil, oregano and parsley, and reach for spices like turmeric and cinnamon for flavor instead of salt.

Healthy fats are also important, so Susie says to use extra virgin olive oil as your primary fat source. Supplement that with healthy fats like those in avocados and nuts, and for omega-3 fatty acids, salmon, sardines and mackerel are all fair game.

Though you should make seafood your main source of protein, you can add other animal proteins into your diet. Moderate consumption of poultry, eggs and dairy products is okay, but limit your intake of red meat and processed meats like sausage or bacon.

Since clean eating is key to the Mediterranean diet, you unfortunately have to give up sugary drinks, snacks and highly processed foods. And while cheesecake is out of the question (sigh), you can eat fresh fruit and honey to satisfy your sweet tooth.

Ketogenic (keto) diet

High-fat and very low-carb meals are the centerpiece here. The idea is to get your body into a state called ketosis, Susie explains, where fat, instead of carbohydrates, is used as your primary energy source. “When the carbohydrate intake is drastically reduced, the body depletes its glycogen stores and starts breaking down fat into molecules called ketones in the liver,” she explains. “These ketones then become the body’s main energy source, replacing glucose.”

Here’s how your key macronutrient ratios should look on the keto diet:

• 70-80% of your total daily calories should be from healthy fats like avocados, nuts, seeds and oils.

• 10-20% should come from protein. Susie says this should be a moderate intake to preserve muscle but avoid any excess protein that can be converted into glucose.

• 5-10% will be from carbohydrates — that’s around 20-50 grams of net carbs per day.

Says Susie, while there are benefits to the keto diet, such as weight loss and blood sugar and insulin control, the risks outweigh the benefits. Lack of fiber from not consuming enough fruits, whole grains and legumes could cause constipation and lead to deficiencies in vitamins B and C and minerals like magnesium. She warns that you might even experience what some people call “Keto Flu” as you adjust to the diet — temporary symptoms like fatigue, headache and irritability.

Talk to your doctor before starting the keto diet to make sure nothing in your medical history will make it particularly unsafe. Once you get the okay, there are foods you’ll want to incorporate into your diet, and what to leave out.

Include healthy fats like avocados, olive oil, coconut oil, butter, ghee and lard. You’ll get your protein intake from fatty cuts of meat, poultry and fish, as well as eggs and full-fat dairy products like Greek yogurt. Stick to low-carb veggies like leafy greens, broccoli, cauliflower, zucchini, asparagus and peppers, and of course low-sugar foods like berries and unsweetened drinks.

As previously stated, you’ll want to avoid high-carb foods at all times. These include your beloved bread and pasta, and even rice, grains, and starchy vegetables like potatoes. Sugary foods and drinks are a big no-no, so say goodbye to cakes, fruit juices and nearly all fruits. Oh, and that Starbucks white mocha coffee creamer you rely on as your morning pick-me-up? Nope! Lastly, packaged snacks like chips and anything with trans fats and unhealthy oils (think vegetable oil) should be banished from your pantry.

Whole30 diet

This isn’t actually isn’t intended to be a permanent diet so much as a way to identify which foods are causing gut problems or other sensitivities. However, if you have any medical conditions like diabetes or kidney issues, Susie recommends consulting a healthcare provider or dietitian before starting.

As its name suggests, the Whole30 is all about eating whole, unprocessed foods, and you should put it in effect for 30 days, during which you’ll eliminate certain things altogether, including sugars and sweeteners; all grains; dairy (except butter); legumes; alcohol (including for cooking) and additives like carrageenan, MSG and sulfites. And if you sneak a cupcake or beer at any time, you’ll have to start your 30 days over. So, yeah, it’s definitely a bit restrictive, but you only have to endure it for a month to get the information you need.

Once you clear your kitchen of the above-mentioned items (or at least shove them aside), Susie says to stock up on non-starchy vegetables, fruits in moderation, high-quality meats, seafood and eggs, avocados, nuts (but not peanuts … which are actually legumes, not nuts, but I digress), seeds, olives and healthy oils.

After you cross the 30-day finish line, there’s a second phase where you’ll reintroduce those eliminated food groups one at a time to see how your body responds. This is how you’ll identify any sensitivities or intolerances to specific foods.

Paleolithic (paleo) diet

If you’re interested in aping the eating patterns of our hunter-gatherer ancestors, paleo is a great way to start. At least, that’s the idea. The goal here is to eat whole, unprocessed foods that were available around 2.5 million years ago, also known as the Paleolithic or Old Stone Age. Susie says the diet “aims to support optimal health by aligning modern eating habits with the evolutionary diet of early humans.”

That means you’ll need to rid your pantry of ultra-processed foods and instead fill it with natural and nutrient-dense options. That includes grass-fed meat, poultry and wild-caught fish (no, you don’t have to catch the fish yourself), eggs, fruits and non-starchy vegetables. Nuts (again, minus peanuts) and seeds, along with avocados, olive oil and coconut oil should serve as your healthy fats. For sweeteners, you’re allowed small amounts of honey or maple syrup, as long as they’re all-natural.

Here’s what you’ll need to toss in the trash to avoid temptation: all grains, legumes, dairy (unless it’s all-natural butter), refined and processed foods, vegetable oils and trans fats, and, of course, alcohol. Natural wine is the one exception to that rule, though Susie says it’s generally discouraged.

The paleo diet is, like other trendy regimens, very restrictive, so it may be hard to maintain. And since you’re cutting out all grains, legumes and dairy, Susie says it could lead to deficiencies in fiber, calcium and vitamin D. She notes that long-term health outcomes of the Paleo diet are still being debated, as critics argue that some modern versions don’t fully mimic ancient eating patterns.

Intermittent fasting

Fasting is practiced by many people around the world, usually for religious reasons. However, in the US, intermittent fasting has become a weight-loss tool, if not a diet in the traditional sense, because it limits when you can eat, rather than what you can eat. So that’s great news — you can still scarf down anything you’d like. However, make sure you’re still fueling your body with healthy things like fruits and vegetables. But adjusting to a new eating schedule might take some time.

There are a few popular intermittent fasting methods to choose from. Note that the Mayo Clinic says fasting is safe for many people but it’s not recommended if you’re under 18, have a history of eating disorders or if you’re pregnant or breastfeeding. You should also avoid fasting if you have medical conditions like diabetes or hypoglycemia. As with any new diet, always consult your doctor before starting.

1. 16/8 method (time-restricted eating): Eat during an 8-hour window (for example, 12 p.m. to 8 p.m.) and fast for 16 hours. Susie says this one’s a great option for beginners because it’s simple.

2. 5:2 diet: Eat normally for 5 days a week and restrict calories to 500–600 on 2 non-consecutive days.

3. Alternate-day fasting: Fast every other day, often allowing only about 500 calories on fasting days. This one may be difficult to sustain long-term, Susie says.

4. OMAD (one meal a day): A stricter version of time-restricted eating, where you chow down within a 1-hour window and fast for the remaining 23 hours.

With any of these, especially numbers 2-4, you’ll face challenges at first. When any of my own family members have tried fasting, I’ve noticed they’re more irritable and generally stay away from others during meal times when they can’t eat.

Vegan diet

Obviously, if you’re a fan of red meat, poultry and eggs, this is probably not the one for you. But if you’re ready to make a drastic change and want to be more sustainable in your food habits, I’ll walk you through what it takes.

Going on a vegan diet means you’ll need to eliminate all animal-derived foods from your kitchen and eat a plant-based diet. That means avoiding meat, seafood, all dairy products, eggs and even honey. Some vegans even consider gelatin, traditional Caesar dressing (because of the anchovies) and marshmallows to be off-limits.

Instead, you’ll focus on eating fruits and vegetables, whole grains, legumes, nuts and seeds. Of course there are plant-based alternatives like oat milk, almond milk, plant-based meats, tofu and vegan cheese.

Challenges with this diet, Susie says, are potential deficiencies in vitamin B12, iron, zinc, omega-3 fatty acids and protein. It could be helpful to meet with your doctor or a registered dietitian to make sure you’re meeting your nutritional needs. And beware: Not all vegan foods are actually “healthy”: Oreos are famously vegan, and many meat alternatives are still high in sodium.

Vegetarian diet

Much like vegans, vegetarians also cut out meat and seafood from their diet, but they’re still allowed to eat animal-derived products like eggs and dairy. There are also several variations of a vegetarian diet, such as lacto-ovo vegetarians (only dairy and eggs), lacto-vegetarians (dairy, but not eggs) and ovo-vegetarians (eggs, but not dairy).

Any vegetarian diet will likely present a few challenges, Susie says. This includes nutrient gaps in omega-3 fatty acids, iron and vitamin B12, depending on whether you cut out eggs and dairy. There’s also a risk of overreliance on processed vegetarian foods, which can be high in sodium and low in nutrients. Be careful what you purchase and always read the label.

Pescatarian diet

Like the vegetarian and vegan diets, the pescatarian is primarily plant-based. However, you can eat seafood, so you’ll still get adequate protein and omega-3 fatty acids. Land-based meat is excluded, but you can have all the dairy and eggs you’d like.

Otherwise, stick to wholesome foods like fruits and vegetables, grains, nuts, seeds, legumes, salmon, tuna and shrimp.

If you decide to try the pescatarian diet, know there are still some concerns and challenges. You may need to use supplements to acquire those nutrients, such as iron, that you’re no longer getting from meat. Susie says you should also be aware of potential mercury and toxin exposure from certain fish — swordfish, shark and king mackerel are the biggest culprits. She notes there are also some sustainability concerns with overfishing, which has an environmental impact and may negate your rationale for cutting meat in the first place.

While these 9 diets are popular right now, there are so many new ones cycling in and out. So if none of these peak your interest, talk to your nutritionist to find a plan that’s right for you.