Interest in different diets like vegetarianism or veganism has been around for centuries. Some diets stem from religious beliefs; Hindus abstain from eating meat because it hurts other lifeforms, while the Mahayana school and other forms of Buddhism do it to help achieve enlightenment. Others do it for weight control or as part of their fitness routine.
Some diets are indeed helpful, while others don’t show benefits and fade into obscurity. The ones that do stick around, though, do so for good reason. For example, the keto and Mediterranean diets are both clinically used to help patients with Alzheimer's and epilepsy. The Vegan Society, the oldest vegan association in the world, uses the vegan diet to promote good health and fight animal cruelty.
With rising health concerns like obesity, metabolic issues, and age-related diseases, re-thinking how you eat may not be such a bad idea.
However, we should note that before changing your eating lifestyle, you should conduct thorough research. Always consult a medical or nutrition professional to ensure that you’re prepared for any potential side effects, such as vitamin and mineral deficiencies.
To create our list, we scoured the web and dug into medically reviewed articles. There are a few mainstay diets as well as several newcomers we cover. So before you start your newest diet, check out the top diet trends of 2020.
1. Keto Diet
The keto diet is a low-carb, moderate protein, and high-fat diet that helps people lose weight by shifting the body's fuel source. The low-carb diet helps transition the body into ketosis, using stored fats as the primary fuel source instead of carbohydrates.
When starting the keto diet, you may experience symptoms of the keto flu. The effects of the keto flu can last one to four weeks as the body shifts into ketosis. You may feel nausea, brain fog, headaches, dizziness, and restlessness. But, once complete, dieters report feeling energized and clarity of mind.
The diet is moderately restrictive, but the keto food list permits eating foods with healthy fats and lots of leafy greens.
The keto diet omits grains, starchy vegetables, and most dairy products. It does allow for a small consumption of alcohol. Keto dieters that do drink are advised to stick to one to two glasses of the occasional lite beer or clear spirits.
What the Research Says:
The keto diet can help with weight loss by excluding processed foods. Medically, it’s been featured in a variety of studies. Some of the findings include:
- Keto has been used to help prevent seizures for epileptic patients.
- Studies have shown that ketosis can help stabilize brain function in young adults (under the age of 50), which may help reduce symptoms of Alzheimer's and dementia.
- Eating a ketogenic diet can help reverse Type II diabetes and improve symptoms of depression.
- Some doctors use the keto diet to help reduce alcohol cravings for patients with an alcohol disorder.
- Regularly following a ketogenic diet can help activate T cells to combat influenza (flu).
2. Mediterranean Diet
The Mediterranean diet is more of an eating style, rather than a diet. The flexible lifestyle is based around the eating habits of countries around southern Europe like Italy, Greece and Southern France.
The predominantly plant-based diet focuses on eating foods high in healthy fats, fruit, nuts and seeds, and small amounts of meat. On average, you can expect your daily caloric intake to be 35 to 40 percent from fats. This means eating food that are rich in omega-3 fats, like fish, olive oil and nuts.
What the Research Says:
Unlike some low-carb diets, the Mediterranean diet is known for helping dieters keep weight off long-term due to the changing of eating habits, not just switching out foods. Since this is a lifestyle, you can eat this way for your whole life.
Some other findings include:
- The Mediterranean diet is recommended by some doctors to older patients, helping to delay the onset of Alzheimer's and protect against cognitive brain decline.
- Some studies have shown that eating an omega-3 rich diet is linked with lowering internal body inflammation.
- Dieters that eat the Mediterranean way will be happy to know that it does allow for the consumption of one to two glasses of wine a day for heart and gut health, and potentially for reducing risk of obesity.
3. Plant-based Diet
People who follow a plant-based diet generally consume vegetables, fruits, seeds, nuts, grains and legumes.
But plant-based diets come in all shapes in sizes. A 2018 Gallup Poll reported that 5 percent of the United States identifies as vegetarian. There are many variations of vegetarianism (vegan, lacto-ovo vegetarian, ovo-vegetarian and lacto-vegetarian) and all have different eating protocols. Some are more structured than others, allowing for dairy but not eggs, for example. Eating restrictions are usually based around your motivations behind choosing the lifestyle.
Since meat is not present in most plant-based diets, protein can be obtained from sources like soy, tofu and beans. For example, a vegetarian or vegan athlete could consume a pea protein shake after a workout.
Eating large amounts of protein has become a cornerstone for many weightlifters and exercise enthusiasts, but thankfully you don’t have to stock up on red meat to get your fix. Many grocery stores cater to this lifestyle as well, with full aisles of veg-friendly meals and ingredients to shop.
What the Research Says:
Since the plant-based diet has been around for a while, it has garnered some interesting results from the scientific community:
- The Journal of the American College of Nutrition conducted a study and found that consuming a plant-based diet is linked to healthy aging.
- If you suffer from gut problems, eating a plant-based diet has been linked to protecting and improving healthy gut bacteria.
- Medical studies have shown nutrient deficiencies that could result from eating plant-based diets, so it’s important to consume nutrition supplements like iron and B12 to prevent vitamin and mineral deficiencies. (Remember to always speak with a medical professional/nutritionist when considering supplements).
4. Flexitarian Diet
The flexitarian diet is a semi-vegetarian way of eating — you eat mostly plant-based products, while still indulging in moderate amounts of meat. There are no specific caloric or macronutrient requirements, but flexitarians consume the same foods that they would as a vegetarian or vegan.
What sets flexitarians apart from vegetarians, vegans and pescetarians is that they allow for the moderate consumption of meat, fish or poultry and other animal products. Like most other diets, flexitarians consume low amounts of sweets and added sugars.
What the Research Says:
Eating on the flexitarian diet can be seen as "the best of both worlds." It allows dieters to focus largely on plant-based foods, while still indulging in meat. A few major findings include:
- The diet aligns with the 2015–2020 Dietary Guidelines for Americans because of the core emphasis on eating fruits and vegetables.
The Université Paris-Saclay and Stanford University conducted a research study that showed eating on a flexitarian diet can provide sufficient protein intake, compared to other plant-based eating lifestyles.
5. Macro Diet: If It Fits Your Macros (IIFYM)
If it fits your macros (IIFYM) is a flexible eating plan that lets you eat whatever you want, as long as it fits your daily macronutrients (nutrients used by the body for maintenance functions). Dieters focus on reaching caloric totals by counting daily macronutrient balance from proteins, carbs and fats.
Food consumption is based on the type of training and rest days. So, on workout days, you’ll consume more carbohydrates (or fats) than on rest days.
The IIFYM was originally created and brough to the mainstream by Anthony Collova, and various other strength camps.
Macronutrient counting became popular in fitness circles due to weightlifters wanting to stay lean, but not have to eat with constant restrictions. It gives dieters the freedom to eat most foods (be sure to make healthy choices) for reaching and maintaining weight goals without starving.
For example, if you wanted to gain mass, you could consume primarily carbohydrates, moderate protein and low fats. Conversely, if you were trying to cut weight, you would consume large amounts of protein, moderate fats and low carbohydrates.
What the Research Says:
While there isn’t any data specifically done on IIFYM, some of the core principles have been covered in some studies:
- Some research has claimed that lowering calorie intake leads to short term weight loss. Though other studies have found that manipulating macros can actually effectively help you lose weight.
- Research studies have shown that occasionally indulging during cheat meals could help with self-regulation and maintain motivation.
- Studies have shown that people are good at judging food quality, but struggle with identifying foods that are energy density rich.
6. Paleo Diet
The paleolithic diet, or "paleo" for short, is a nod to our hunter-gatherer ancestors. Dieters consume only lean meats, fish, limited fruits, vegetables, seeds, eggs, healthy oils and nuts.
The paleo diet also restricts processed foods, grains, added sugars, condiments, legumes, dairy and alcohol. Like plant-based diets, paleo dieters can choose more strict or relaxed eating limits.
The paleo diet became popular in the mainstream after Loren Cordain published the book, The Paleo Diet: Lose Weight and Get Healthy by Eating the Food You Were Designed to Eat, in 2001. The diet then rose in popularity via the CrossFit community due to reported improved physical performance and mental clarity.
When looking at the eating structure, Crossfit uses specific eating protocols like avoiding most vegetable oils to keep the body fueled and ready for action.
Today, meal prep delivery services, nutrition companies, and various other influencers help spread the word about the benefits of eating paleo.
What the Research Says:
Like a few other diets on this list, the paleo diet does overlap a bit with others but there are some interesting studies on the paleo diet specifically:
- One study compared eating on the paleo diet to the Mediterranean diet. Results found that the paleo dieters had reduced risks of colon cancer.
- Besides improved mental clarity and athleticism, studies show that eating paleo can help with weight loss and managing risks of chronic diseases like Type II diabetes and cardiovascular disease.
7. Low-FODMAP Diet
The Low-FODMAP is a short-term elimination diet that helps with irritable bowel syndrome (IBS). FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides and polyols-carbohydrates. These are sugars that the body absorbs poorly, causing symptoms of diarrhea, constipation, bloating and cramping.
Foods like dairy, wheat, beans, lentils and some veggies and fruits are temporarily removed from the diet. After adding them back, your food sensitivity levels are examined. The foods that create the greatest reaction are decreased or removed altogether.
What the Research Says:
The Low-FODMAP diet is not based around weight loss and you won’t see your favorite celebrities talking about it in the news. However, the diet has some interesting findings:
- It has been medically shown to help improve symptoms of IBS.
- A survey of adolescents and teens with gastrointestinal issues and IBS found that after four weeks of eating on the Low-FODMAP diet, some showed signs of improved symptoms.
- One study conducted by Monash University found that the Low-FODMAP diet doesn't work for everyone. So, as interesting as the Low-FODMAP diet sounds, it should only be performed under the care of a doctor, nutritionist or registered dietitian.
8. Dr. Sebi Diet
The Dr. Sebi diet was developed by Alfredo Bowman, also known as "Dr. Sebi." Dr. Sebi was not a medical doctor and did not have a doctorate degree — rather, he was an herbalist.
The Dr. Sebi diet focuses on an African approach to disease, helping to reduce risks of metabolic disease without using Western medicine.
The Dr. Sebi diet is considered controversial due to its restrictive plant-based focus, only allowing for foods from a specialized nutritional guide designed by Dr. Sebi himself.
Similar to Whole30, it is a short-term elimination diet that can't be maintained long-term. For example, the diet does not allow eating meat, legumes or soy, therefore there is little if any protein.
Those following the diet consume carefully selected veggies, fruits, grains, natural oils, seasonings and spices. As a result, cheat days don't exist and animal products and alcohol are off-limits.
9. Intermittent Fasting (IF)
Intermittent fasting (IF) is based on the concept of fasting regularly and consuming foods during timed windows. In fact, if you're a busy individual, you may have performed intermittent fasting on accident by skipping breakfast and having lunch as your first meal.
Similar to the keto diet, you are periodically shifting your body into ketosis, typically fasting for 16 hours and eating within an eight-hour window.
There are also different variations such as eating regularly every other day and restricting calories on the off days. Whichever method you choose to follow, be sure to stay consistent throughout the process. Give you body time to adjust to the new eating routine.
Intermittent fasting became popular in the fitness world among bodybuilders and bikini competitors that utilize macronutrient timing to control their eating. Fit celebrities like Dana Linn Bailey, Hugh Jackman, Beyonce, Terry Crews and Nicole Kidman swear by the diet.
What the Research Says:
The intermittent fasting diet is quickly gaining popularity and there are a handful of great studies out there regarding its effectiveness. So, let’s take a look at some of the findings:
- The New England Journal of Medicine released a study reporting that intermittent fasting could provide longevity and help increase stress resistance.
- The University of California, San Diego conducted a study and found that intermittent fasting promotes weight loss and conscious eating.
- A research study found that intermittent fasting can help reduce the risks of obesity.
10. Whole30 Diet
The Whole30 is a short-term elimination diet that cleanses the body from sensitivities by eating only whole foods. The Whole30 website emphasizes that it is not a great "weight loss diet,” but you may see some reduction in body fat and size.
Dieters on Whole30 eat foods like lean meats, fresh fruit, healthy fats and lots of veggies. The restrictive diet eliminates sugars, alcohol, legumes, grain and dairy products. So, you will be eating from the outside aisles at the grocery stores and making meals from recipes on the website.
If the Whole30 way of life sounds familiar, it's because it can be seen as a more restrictive version of the paleo diet. Both groups primarily consume nuts, seeds, lean meat, fish and vegetables. However, it should be known that the Whole30 is a temporary cleanse. This means that it shouldn’t be maintained for a long period of time.
While the diet has been used in some medical circles to help with food sensitivities, it hasn't received a warm welcome outside, due to the diet's strict rules. In 2019, U.S. News ranked it 33rd out of their list of the 40 Best Diets by a panel of experts.
Whole30 dieters should be wary about re-introducing foods back into their diet after completing the Whole30 program and take note of any physical changes.
No peer-reviewed medical studies have been formally done on the Whole30 diet.
How to Choose the Right Diet for You
Before starting one of the diets listed above, do your research first. Make sure that you understand what it is, the pros and cons, and how it could impact your body. For the best results, seek guidance from our doctor, nutritionist or registered dietician.
Also, make sure that the eating style that you choose is realistic and attainable. Consider things like your budget for food or the time commitment needed. Choose diets that can fit well with your lifestyle.
When considering weight loss and diet trends, some may provide short-term results, but weight can return.
View weight loss as a lifestyle change, one that is realistic and can be maintained long-term. Eating will only get you so far on your journey. It should also be paired with strength training workouts and plenty of sleep for recovery.
You’re not going to know what you will look or feel like until the end of the ride. Be honest with yourself and understand that this is all part of a fitness journey. A healthy diet that’s right for you can be part of the bigger picture of your overall well being.