Do the Three Most Popular Diets Really Work?

Do the Three Most Popular Diets Really Work?

Do the three most popular diets really work? There’s so much health, nutrition and fitness advice out there, and some tips seem to contradict others. Additionally, trends are constantly changing, and it’s hard to know what is actual good advice and what is just a passing fad.

Here, we’ll break down the three most popular diets. These eating plans each come with some benefits that science shows may help your health. They all also come with advice that may be ineffective or even harmful for certain groups of people. Paying attention to the parts that work may help you learn how to maintain a healthy weight.

What Are the Most Popular Diets?

One way to tell which diets are the most popular is through surveys and studies. One such study is conducted each year by the International Food Information Council (IFIC). In 2020, the IFIC surveyed over 1000 Americans about their food habits and beliefs. 43% of Americans said that they had tried a diet or eating plan within the last year. This number was an increase compared with the past few years.

The 2020 IFIC survey found that the three most popular diets were:

  1. Intermittent fasting
  2. Clean eating
  3. Ketogenic or high-fat diet

Of course, just because a diet is popular doesn’t mean that it works for all or even most people! Here, we will dive into the science behind each of these diets and explore whether these eating plans are worth the time and effort.

Intermittent Fasting

How Do You Try Intermittent Fasting?

Intermittent fasting doesn’t involve counting calories, eating certain foods, or avoiding certain items. This type of diet doesn’t tell you how or what to eat – it just tells you when to eat. However, the intermittent fasting diet is much more effective if — when the “eating” window occurs — one eats healthier options rather than higher caloric, heavily processed and unhealthier options. That is, if one engages in eating these very unhealthy options during this time, the effects of the intermittent fasting diet is diminished.

There are many possible intermittent fasting plans you can follow. Some examples are:

  • Alternate day fasting: With this method, people fast every other day. On fasting days, a person only eats a couple hundred calories or doesn’t eat at all. On other days, a person eats normally.
  • 5:2 diet: This is a type of alternate-day plan where you eat normally for five days per week. On the remaining two days, you eat two very small meals totaling 500-600 calories. For example, you may decide to fast on Tuesdays and Fridays.
  • Eat-Stop-Eat: This plan involves fasting for a full day once or twice a week.
  • 16/8 method: On this plan, you fast for 16 hours and then eat all of your meals within an 8-hour window. For example, you may skip breakfast, and then eat a couple of meals between noon and 8:00 pm. Other similar plans exist, such as the 14/10 method, where you fast for 14 hours and eat for 10 hours.

Many people are more successful at IF when they ease into it more slowly. Starting with the 16/8 or 14/10 method, or even just starting with skipping breakfast, may be easier than jumping right into alternate-day fasting.

What is the Science Behind Intermittent Fasting?

When you avoid food for a bit, several changes happen within your cells. Right after eating, the level of sugar in your blood gets higher. Your cells use this sugar to make energy. When you fast, you have less sugar in your blood, and your cells switch from using sugar to using stored fats as fuel. Additionally, during fasting periods, your cells can more easily heal damage.

What Are Possible Benefits of Intermittent Fasting?

IF seems to help boost metabolism, spurring your body to burn more calories. Many clinical studies have shown that IF can help people shed pounds. This seems to be especially true for people who already weigh a little more. Additionally, when fasting is combined with strength training workouts, it can help people lose more fat without losing muscle.

IF may also lead to other health benefits, including:

Additionally, fasting plans may be easy to follow. You don’t have to plan or prep specific meals, or keep track of your foods. You can still easily visit restaurants and enjoy your favorite foods, which may be more difficult when following other diets.

Are There Any Cons to Intermittent Fasting?

Fasting can lead to many side effects, like extreme hunger, headaches, problems focusing, irritability, or bad breath. However, side effects may start to go away after several weeks.

These side effects can make fasting hard to stick with. In clinical trials, people often eat more than they are supposed to on fasting days. Some studies have found that that IF leads to a larger drop in pounds compared to traditional calorie-cutting diets, while others have found that both diets produce similar amounts of weight loss and other health benefits. This means that if you’re more likely to stick with a standard low-calorie diet than an intermittent fasting plan, it may be better to just do that.

People who try intermittent fasting should also know about other possible health issues while following this plan. Fasting can increase levels of LDL (“bad”) cholesterol. Fasting can also be risky for people with certain health conditions, such as diabetes. If you’re interested in trying IF, talk to your doctor first to get advice on how to fast safely.

Clean Eating

The second most popular type of diet in 2020, according to the IFIC survey, was clean eating. These diet plans emphasize eating whole foods that are in their natural state, as opposed to processed foods. People who follow clean eating plans say that they can lead to weight loss and better health.

What Foods Do You Eat On a Clean Eating Plan?

“Clean eating” does not refer to just one specific diet. It’s more of a loose, flexible set of guidelines. Clean eating plans encourage people to eat a lot of vegetables, fruits, whole grains, non-fatty proteins, and healthy fats. These foods should also be eaten in their natural forms, without being altered, whenever possible.

People on clean eating plans avoid foods that are processed. Any time a food has been changed from its original form, it’s not considered to be as “clean.” For example, clean eating says that eating whole fruits is better than drinking fruit juice. There are some exceptions, however. Frozen veggies and fruits are usually picked and frozen at their freshest, and are considered clean eating. Additionally, while cooking is technically a form of processing food, it’s fine to cook your meals when you’re on a clean eating plan. Examples of processed foods to avoid when following clean eating plans include:

  • Pre-made, pre-packaged, ready-to-eat foods
  • Frozen or microwaveable meals
  • Items with additives and preservatives
  • Foods with added salt, fat, or sugar

Check the labels of the foods you eat. If there are multiple ingredients you don’t recognize, that item may not be part of a clean eating plan.

Does a Clean Eating Plan Work?

Clean eating has not been directly tested in clinical trials. However, some of its principles have been.

People who eat a lot of processed foods are more likely to be obese. However, this doesn’t necessarily mean that cutting out processed foods will automatically make you start dropping pounds – it may be more complicated than that. Clean eating as a weight loss strategy has not yet been well-studied. However, clean eating is similar to the Mediterranean diet, which also emphasizes whole, fresh foods. Many studies have shown that the Mediterranean diet can help people lose fat and achieve and maintain a healthy weight.

Clean eating principles can potentially have other health advantages, too:

Should You Follow a Clean Eating Plan?

Clean eating hasn’t yet been well-studied enough to know whether or not these eating plans generally lead to weight loss. However, clean eating plans can likely provide many health benefits.

It’s important to consider that clean eating means avoiding ready-made meals. Many restaurant or fast-food meals are also off the table. This means that you will need to cook most of your meals at home. This may be a good thing. It probably means that you’ll be saving money on your food bill. However, if you don’t have a lot of extra time to cook, it might be difficult for you to follow this plan.

Ketogenic or High-Fat Diet

A ketogenic diet, often simply called “keto,” is an eating plan in which people control the amounts of carbohydrates, proteins, and fats that they eat. People following this diet will eat much fewer carbs and more fats than usual.

What Is the Science Behind Keto?

Keto works in a similar way as fasting. The cells in your body typically use carbohydrates, including sugars, as fuel. When cells aren’t getting enough carbs, they turn to a process called ketosis. During ketosis, fats are converted into molecules called ketone bodies, which are then used by cells to make energy. During this time, the body also stores less sugar and fat.

Do Keto Diets Work?

Several studies have found that high-fat diets can lead to greater amounts of weight loss than low-fat diets. Keto may help you lose weight by burning extra fat and by helping decrease your appetite and encourage you to eat less.

Ketogenic diets help with other health issues, too. These diets have been used for nearly 100 years to help treat epilepsy. Modern studies have also found other benefits. Keto can:

What Are Some Potential Problems With the Keto Diet?

Keto can lead to side effects like nausea, tiredness, sleeping problems, and constipation. However, these side effects usually don’t last more than a few days, or occasionally up to a couple of weeks.

Additionally, only a couple of studies have taken a deep look at how ketogenic diets affect health long-term, and we know that there are several long-term side effects that must be taken into consideration before one starts a ketogenic diet. These include the following: fatty liver (hepatic steatosis), low protein levels in the blood (hypoproteinemia), kidney stones (renal calculi), and certain mineral and vitamin deficiencies and it is possible that there are other long-term side effects that we don’t yet know about. Additionally, keto can increase your cholesterol levels, so if you already have high cholesterol, this diet may not be a good fit for you.

How Do You Follow a Keto Diet?

If you want to try keto, you will need to eat a lot more fat and a lot fewer carbs. There are different keto plans that advise eating different amounts of these nutrients. Many plans encourage people to eat foods in the following ratios:

  • 55-60% of the calories you eat should be fats
  • 30-35% of your calories should be proteins
  • 5-10% of your calories should be carbohydrates

In order ensure you’re hitting these goals, you will have to track everything that you eat and drink. Several websites and apps can help by allowing you to log foods. These tools can then calculate how many of your calories come from fats, proteins, and carbs, and help you see if you are on track.

Will Any of These Diets Help You?

Most diets give people good results after six months. They often help people lose weight, lower blood pressure, and improve cholesterol levels in the short term. However, in the long term, these benefits often disappear. People gain back the weight and their blood pressure and cholesterol levels go back to where they were before.

One reason is that diets are very hard to stick with. It’s somewhat easy to see results when a diet feels new and exciting. It’s harder to have momentum. For this reason, it may be better to build up eating habits that you know you’ll be able to stick with. Take a look at your needs and preferences, including how much time you have available to cook your own meals and the types of foods you usually like to eat. Try to find a diet that doesn’t involve a lot of big changes, and start slow.

Fasting, clean eating, and keto can all probably help you maintain a healthy weight and improve your health. It’s always a good idea to talk to your doctor before starting a new diet or eating plan, because they can help you do so safely and minimize possible health problems.

If you would like to learn more, schedule a consultation with Dr. Connor

Weight Loss and Health Benefits of Intermittent Fasting

Weight Loss and Health Benefits of Intermittent Fasting

Intermittent fasting has become very popular in recent years. Many people use intermittent fasting to lose weight, but scientific research shows that it can have many other positive health effects as well.

Intermittent fasting is a type of eating plan based around periods of eating and periods of fasting, or avoiding food. Whether you realize it or not, you already go through a period of fasting over the course of a typical day: you fast while you sleep. When following an intermittent fasting plan, you purposefully make these fasting periods longer, by skipping certain meals or by not eating at all on some days. Intermittent fasting isn’t like a traditional diet plan – it doesn’t tell you exactly which foods to eat or how much food to have. Instead, intermittent fasting tells you when to eat.

Why are People Trying Intermittent Fasting?

Intermittent Fasting: Weight Loss and Health Benefits
Experiments throughout the 20th century showed that eating fewer calories each day, also known as calorie restriction, could lead to longer life for multiple different types of animals. The studies also found that calorie restriction could reduce symptoms of several different kinds of diseases. In recent years, researchers have begun clinical trials in humans to try to discover whether calorie restriction can offer us the same results. Many of these studies have led to positive health benefits.

In the past couple of decades, researchers have realized that one of the reasons calorie restriction may be effective is because it often leads to long periods of fasting. Therefore, many new studies are currently underway to study whether intermittent fasting can also lead to good health and long life.

Weight Loss and Muscle Gain

When it comes to dropping pounds, intermittent fasting is at least as effective as cutting calories. In fact, some clinical trials have found that fasting may lead to even greater amounts of weight loss. Additionally, people with a higher BMI are especially likely to shed pounds when on an intermittent fasting eating plan. Researchers think that the reason fasting helps you lose weight is that it can boost metabolism.

In recent years, intermittent fasting has become very popular among health and fitness enthusiasts, with many personal trainers and fitness communities recommending the diet. Scientific research shows us there is probably good reason for this. Multiple studies have looked at the combination of intermittent fasting with resistance training, which includes strength-building exercises such as weight lifting and bodyweight exercises. The studies found that the combination of fasting with resistance training led people to burn more fat and maintain or possibly even build more lean muscle.

Other Health Benefits

Intermittent Fasting: Weight Loss and Health Benefits

Heart Health

Intermittent fasting can boost heart health in several ways. It can help people lower blood pressure, heart rate, cholesterol, and insulin levels. Fasting also drops levels of fat and sugar in the blood. All of these factors affect a person’s likelihood of developing heart disease or of having a heart attack or stroke. It’s possible that intermittent fasting eating plans could reduce a person’s risk of disease by keeping these factors under control.

Additionally, fasting may help lessen the impact of a poor diet. For example, eating a lot of saturated fat increases a person’s risk of heart disease. When mice are fed a high-fat diet, they develop obesity, high insulin levels, and fatty liver disease. However, mice that are fed a high-fat diet but are only allowed to eat for limited periods of time each day don’t have these heart disease risk factors.

Interestingly, a few studies have looked at the effects of fasting in religious populations. Studies of Muslims and Latter Day Saints found that people were less likely to have heart disease or heart failure while going through a religious fast.


Some studies have also shown that intermittent fasting plans can improve insulin sensitivity and blood sugar levels, meaning that their bodies can better digest and use sugar. When the body becomes more efficient at metabolizing sugar, a person is less likely to develop diabetes. However, these studies have only looked at short-term health effects, and some other studies have shown mixed results. It’s not entirely clear yet whether intermittent fasting can directly lower a person’s diabetes risk in the long run.

Brain Disorders

Intermittent fasting may help the brain age in a healthy manner by encouraging brain cells to grow and form new connections. Animals who fast are better protected against injury and have lower rates of Alzheimer’s disease and Parkinson’s disease.


Initial laboratory studies have found that fasting can starve tumor cells and activate genes that protect cells from cancer. In animals, intermittent fasting leads to fewer tumors, less cancer growth, and increased sensitivity of tumors to treatments like chemotherapy. In human studies, very early results have shown that fasting diets may shield cells from damage and lead people to have fewer symptoms after undergoing chemotherapy. These early studies haven’t yet been able to tell us whether intermittent fasting can be an effective cancer treatment in humans. However, many clinical trials studying this question are in progress.

Other Effects

Early evidence also shows that intermittent fasting may reduce symptoms of other diseases such as asthma, arthritis, and multiple sclerosis, and may help heal wounds more quickly.

Intermittent fasting may also have several other health benefits, such as:

  • Cells are more protected from damage
  • Cells can more easily repair themselves
  • The body increases levels of antioxidants
  • Cells can more efficiently produce energy
  • Old or damaged cells are removed from the body and recycled
  • Lower levels of inflammation

These benefits can lead to better physical and mental health. For example, animal studies show that intermittent fasting leads to much better physical endurance, as well as boosted balance and coordination. Additionally, restricting calories may lead to better brain function and an improved memory.

How Does Intermittent Fasting Work in Your Cells?

Scientists don’t yet completely understand how intermittent fasting works. However, they have come up with several possible ideas to help explain how fasting affects your cells, your body, and your metabolism:

  • Cell Damage: As your cells process food and extract nutrients, they create toxic molecules called free radicals. It’s possible that giving your body fasting periods helps cells produce fewer free radicals. Fasting also allows your body to heal and repair damage.
  • Circadian Rhythms: Your circadian rhythms are part of your body’s internal clock. Your body clock links eating/fasting cycles with the outside day/night cycles. This helps your body maximize its energy during the day, when you’re awake. When our body clocks become mismatched with the outside day/night cycles, problems can result. Studies of intermittent fasting have found that when people eat for a shorter period in the middle of the day, they have health benefits related to better metabolism and heart health, but these benefits aren’t seen when the feeding period is later in the evening when it’s dark.
  • Ketosis: Intermittent fasting can lead to a change in metabolism. After eating, your body uses carbohydrates such as sugars for fuel, and stores the fat. During fasting, sugars are no longer available in the blood supply, so your body starts using up the fat it stored. During this period, the body also produces molecules called ketones that it can also use as fuel. Ketones also help cells work properly by controlling many proteins within the cell, such as growth factors, DNA repair enzymes, and sirtuins, proteins that control many aspects of health and aging.

How Do I Go About Intermittent Fasting?

There are several different types of intermittent fasting eating plans. In general, they fall under two different categories:

  • Alternate-day fasting consists of skipping food for a full 24 hours. This may be done once or multiple times per week. For example, one common fasting plan is the 5:2 diet, where someone fasts for two non-consecutive days in a week and then eats normally for the other five days. Or, someone may rotate every other day between fasting and eating. Some alternate-day plans tell people not to eat anything for the entire day, while others say that eating a couple hundred calories is okay.
  • Time-restricted fasting is when someone fasts for certain hours each day. They may eat for only eight hours and then fast for 16 hours, or eat during a four-hour window and fast for the remaining 20 hours of the day. In this case, fasting means that you completely go without food. However, it’s important to still drink water during this time, so that you don’t get dehydrated. Other zero-calorie drinks such as coffee are also okay to have during fasting periods.

Most intermittent fasting plans don’t tell you exactly which foods to eat during feeding times. However, it’s still important to eat healthful foods while doing fasting plans. Eating more plant-based meals supplemented with healthy proteins such as chicken or fish will amplify the health benefits that come with intermittent fasting. If you are eating a lot of saturated fats, sugar, and salt during your eating periods, you may still be at increased risk for developing several different diseases.

Is Intermittent Fasting Safe?

Many clinical trials have been conducted to look at potential risks of intermittent fasting. So far, researchers haven’t found any major concerns. Even trials of more extreme fasting plans, such as eating zero calories every other day, have reported that fasting seems safe for most people. However, in certain groups of people, intermittent fasting should be approached with caution. No single diet or food lifestyle change is universally appropriate or effective for all people. Depending on one’s individual circumstances, an effective food lifestyle for one person could be harmful if practiced by a person with different personal or medical circumstances so I advise anyone who is considering intermittent fasting to first consult with their doctor.

By way of example, fasting may be risky for people with diabetes, especially for those who are on medications such as insulin that may cause hypoglycemia. Fasting could lead a person’s blood sugar to drop too quickly.

When women try intermittent fasting, some may find that they stop having their period. If this happens to you, try going back to a normal eating pattern and consult your doctor. Additionally, if you’re pregnant, trying to become pregnant, or breastfeeding, it’s probably not healthy for you to try intermittent fasting.

Minor Side Effects

When fasting, it’s common to feel very hungry. In clinical trials, people have also reported other minor side effects, such as:

  • Feeling cold
  • Headaches
  • Feeling light-headed
  • Difficulty concentrating
  • Experiencing mood swings
  • Less energy
  • Bad breath
  • Constipation
  • Not being able to stop thinking about food

While these symptoms may be difficult to deal with, they do seem to go away over time. After a month or so, people tend to not feel as hungry or experience these symptoms.

Bigger Risk Factors

Sometimes, people who try IF eating plans are at risk for malnutrition. Taking vitamin or mineral supplements may help you ensure your body is continuing to get the nutrition it needs. Additionally, make sure to eat sufficient protein during meals, as protein malnutrition is a possible concern.

People trying IF should also be aware of signs of more serious health problems. Talk to your healthcare provider if you become dizzy, nauseous, or weak, or if you have trouble sleeping or faint.

Is it Possible to Do Intermittent Fasting Long-Term?

So far, we don’t know of any safety concerns for healthy people who try intermittent fasting over the long haul. However, it might be tough to stick with this eating plan, as it can be very inconvenient or be difficult to incorporate into your daily routine.

It may help to gradually ease into a fasting eating plan. For example, if you’re doing alternate-day fasting, you could try to eat 1000 calories on fasting days for the first month, 750 calories the second month, and 500 for the third. Or, to gradually take on time-restricted fasting, you could try to gradually extend your fasting time each day. Try fasting for 12 hours every day the first month, 14 hours the second month, and so on until you hit your goal. If you immediately jump into a very restrictive plan, you may have more trouble sticking with the diet.

For best results, work with a registered dietician or nutritionist to come up with an eating plan that works for you. A professional nutritionist can help you make sure you’re getting all of the nutrients you need to stay healthy and see maximum health benefits!

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