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Popular Diet Plans: The What, Why, and How

These days, there’s more diet information than ever out there on the internet and in real life. From social media to Pinterest recipes to your friend’s latest diet, sometimes it seems like the options are overwhelming. It can be so tricky to compare different diet plans and see which one works best for your personal body composition goals.

Say goodbye to confusion: in this post, we dive into four major diet plans with very diverse approaches and offer a summary of each. The diets under consideration here–Ketogenic diet, Paleolithic Diet, Mediterranean Diet, and Whole 30–have different philosophies toward health and wellness, and there’s a ton of misunderstanding about what they entail.

We’ll use science-backed evidence and meal plans to shed light on the details of each of these popular diets. Now you can make your own informed choice about which–if any–of these diet plans will be the best for your goals, priorities, and preferences.

The Keto Diet

Keto: What Is It?

The ketogenic (keto) diet aims to reorient people’s eating habits so that their body uses fat for energy by converting fat to ketones and free fatty acids (FFAs). This natural metabolic state is often referred to as ketosis. Reaching ketosis means you have to limit your carb intake to encourage your body to produce ketones for energy. The keto diet prioritizes eating healthy fats.

The rationale for this diet lies in the fact that most of us are consuming too many carbs.

Carbs are an excellent source of calories and your body’s preferred energy source. But glucose from excess carbs is metabolized by the body and gets stored as fat when unused. If you reduce your carb intake to around 30 to 50 grams of net carbs, it pushes your body to rely on dietary fat as an energy source.

A keto diet works for almost anyone since you can be vegan or vegetarian and still achieve ketogenesis. Other diets patterned after the ketogenic diet include the South Beach Diet, Atkins Diet, modified Paleo, and anything low-carb.

What Can You Eat on Keto?

As a rule of thumb, keto dieters focus on foods that are high in fat and avoid processed foods with trans-fats as much as possible. They also recommend eating fruits that are low on the glycemic index but rich in fiber and eating foods like avocados and berries. Plus lots of green, yellow and red vegetables!

The building blocks:

  • Meat (grass-fed and free-range is better) – pork, chicken, beef, eggs. Vegans will need vegetable protein sources

  • Nuts and seeds

  • High-fat dairies such as cream, whole butter, and hard cheeses

  • Leafy greens

  • Fish and seafood

  • Olive oil, coconut oil, pure butter, vegetable oils rich in omega 3

A keto diet restricts:

  • Any food that’s made of starch (even whole grain, organic bread)

  • Most fruits (since they are high in sugar)

  • Any food that’s labeled with low-fat

  • Vegetable oils rich in omega-6 and low in omega-3

Some keto dieters add alcohol and coffee ( minus the cream, milk, or sugar) in moderation to their diet. Others stay away from it. Experiment with these beverages and figure out what works for you.

What Are The Drawbacks of Keto?

Your body tends to resist change, and side effects, known as the “keto flu”, may arise during the first few weeks of going keto. Symptoms include fatigue, dizziness, and nausea. Think of it as your body’s way of expressing its reluctance to stop relying on carbs and learning to use fat as fuel.

To combat these symptoms, keto acolytes recommend increasing your electrolyte and fluid intake. Bone or vegetable broth consumption is also helpful.

Another side effect of ketosis is hypoglycemia or low blood sugar. Symptoms include feeling tired, hungry, or shaky until your body adjusts to its new fat-burning diet.

Reduced physical performance has been observed during periods of keto-adaptation. A review of studies on ketogenic diets and physical performance concluded that anaerobic (ie, weight lifting or sprint) performance is limited by the low muscle glycogen levels induced by a ketogenic diet. So, if you’re an athlete going keto in-season is likely not the best option for you.

What Are The Benefits of the Keto Diet?

Ketogenic diets can be very useful for reducing body fat, but results will not come overnight. Like all diets that reduce carb intake, weight loss will come quickly during the first two or more weeks, and then you’ll see it slow. That’s because a lot of the initial weight loss is water weight, not body fat. Keto’s benefits lie in the way our body metabolizes food for energy.

When you go keto, your body goes into ketosis, a glycogen-deprived state from the low carb intake. Fat is oxidized to produce energy, resulting in ketones. Unlike glucose, which provides quick bursts of energy, the energy from fat burns slower. As a result, you may avoid sugar crashes right after a high-carb meal being on a keto diet.

A ketogenic diet also helps curb overeating, since unsaturated fats are more satiating. Additionally, studies have shown that ketones have neuroprotective benefits.

A study compared the effectiveness of a low-carb keto diet (less than 10% calories from carbohydrates) to a low-fat diet among obese men and women. The researchers concluded that the low-carb keto diet was effective for short-term weight and fat loss (particularly in men).

Most calorie-restricted diets have catabolic (muscle loss) effects, but keto doesn’t.

In an 11-week study of men who performed resistance training three times a week, researchers found lean body mass increased significantly in subjects who consumed a very low carb, ketogenic diet (VLCKD). Significant fat loss was also observed in the VLKCD group.

Several studies have shown that VLCKD has been shown to reduce the risk of the following:

  • Cardiovascular disease

  • Type 2 diabetes

  • Epilepsy

  • Cancer and tumor progression

  • Polycystic ovary syndrome

  • Neurological diseases such as Parkinson’s and Alzheimer’s

  • Amyotrophic lateral sclerosis

Eat Like Your Ancestors: The Paleolithic Diet

Paleo: What Is it?

“Paleo” refers to the paleolithic (or caveman) era. It’s why the paleo diet is also referred to as the caveman diet. People who follow the paleo diet generally believe that we should eat the way our hunter-gatherer ancestors ate, i.e., unprocessed, whole foods.

Foods to eat:

  • Lean proteins

  • Fish

  • Eggs

  • Vegetables

  • Healthy fats and oils

Foods to not eat:

  • Grains

  • Sugar and high-fructose corn syrup

  • Dairy

  • Some vegetable oils (soybean, sunflower, cottonseed, safflower, corn, and olive oil)

  • Beans and legumes

  • Trans fats

  • Artificial sweeteners

  • Refined carbohydrates

  • Processed foods.

As we mentioned earlier, diets like Paleo follow the principles of Keto of low carb, high-fat diet. So what’s the difference?

The main goal of the keto diet is to enter a state of ketosis, where the body begins to burn fat for fuel. The paleo diet goal is to eliminate modern processed foods for health or weight loss.

What Are The Health Benefits of Paleo?

Research shows that a paleo diet can result in short-term improvements in all five metabolic syndrome components (blood pressure, waist circumference, triglycerides, fasted HDL cholesterol, and serum glucose).

Over a 3-month study period, diabetics who ate a paleo diet showed improved glycemic control and decreased cardiovascular risk factors.

A 2013 study in the Journal of Internal Medicine looked at 10 overweight or obese postmenopausal women who followed a Paleo diet for five weeks. Among other improvements, researchers found a 50-percent reduction of triglycerides stored in the liver, which may result in a decreased risk of cardiovascular disease.

What Are The Drawbacks of Paleo?

Individuals on the paleo diet may be missing out on fiber, vitamins, and minerals that come from a diet that includes healthy grains and dairy products — especially if they eat a paleo diet for an extended period of time.

Grains are an important source of dietary fiber and several B vitamins (thiamin, riboflavin, niacin, folate) and minerals (iron, magnesium, selenium). Dairy foods are great sources of calcium, potassium, and vitamin D when they’re fortified. Without recommended amounts of these nutrients issues with digestion, bone health, energy level, and regular bodily functioning may arise.

Live the Lifestyle: The Mediterranean Diet

Mediterranean Diet: What Is it?

When you think of the word the Mediterranean diet (MedDiet), what comes to mind?

You’re not wrong if you can envision yourself eating freshly-caught fish, plump avocados, olives, creamy mozzarella, and a glass of wine to cap off your evening.

The truth is there isn’t one exact formula for eating the Mediterranean way. In a nutshell, you take into account the traditional food choices, lifestyles, and eating patterns of several countries surrounding the Mediterranean sea.

What to Eat in a Meditteranean Diet

As illustrated in the Mediterranean Diet Pyramid, you’ll find basic food groups that you should focus on while on the MedDiet:

  • Whole grains

  • Fruits

  • Vegetables

  • Legumes

  • Nuts

  • Herbs

  • Spices

  • Healthy fats with emphasis on olive oil.

  • Fish and Seafood at least twice a week. Apart from being an essential source of protein, you’ll also get your fill of heart-healthy omega-3 fatty acids.

These are the foods that you should eat in moderation:

  • Dairy – with emphasis on certain fermented dairy products such as yogurt and traditional cheeses. These are the ones that you should aim to eat frequently in small portions.

  • Eggs and poultry

  • Red meat with a focus on lean cuts

  • Sweats

  • Wine – Women can have up to one glass per day while men can have up to two.

What Research Has to Say About the Mediterranean Diet

For decades, the Mediterranean diet has been the focus of careful study and scrutiny.

To begin, a study on 248 healthy women published in the European Journal of Clinical Nutrition concluded that, when combined with exercise, the Mediterranean diet could help reduce body fat accumulation in the lower body, which will contribute to a lower overall health risk.

Furthermore, a meta-analysis published in the journal Metabolic Syndrome and Related Disorders concluded that the MedDiet “may be a useful tool to reduce body weight, especially when the diet is energy-restricted (eating fewer calories than normal), associated with physical activity, and more than 6 months in length.”

These findings indicate the MedDiet is not just another fad diet. Think of it as a more sustainable way of building healthy eating habits. Plus, it has been consistently proven by research to reduce the incidence of lifestyle diseases and promote a healthier body composition!

Reset Your Eating Habits: Whole30

Whole30: What Is it?

Whole30 is essentially an elimination diet, which is most often used to uncover food allergies or sensitivities. The program’s website says that the main purpose of the diet is to help participants find out what foods they might be sensitive to. Weight loss is an added benefit, the program says.

The program is based on cutting out entire food groups such as dairy, grains, beans, refined carbohydrates, and added sugars for 30 days to “reset” your relationship with food and help you pinpoint foods that might be affecting your health. During the plan, you can eat meat, seafood, eggs, veggies, and small amounts of fruit, oils (like olive oil or coconut oil), nuts, and seeds. The diet does not set a calorie limit.

It strives to alleviate issues like bloating, allergies, chronic pain, hormonal imbalances, skin problems, and more.

However, there isn’t any scientific evidence supporting their claims, only anecdotal evidence in the form of testimonials.

What Are The Benefits of Whole30?

  • It emphasizes unprocessed foods and teaches you to stop eating out of packages.

Since you’re essentially banned from the inner aisles of the grocery store, the program teaches you to make and enjoy meals that use only whole foods. Many “Whole30-approved” recipes are both delicious and extremely nutrient-dense.

  • It promotes eating healthy foods.

This is where it is easy to give a nod of approval to Whole30. A diet rich in whole foods — and not in sugar, salt, and chemicals — is a surefire way to boost your energy level, decrease fatigue and brain fog, and perform well in all areas of life.

  • It can help you identify food intolerances.

The Whole 30 diet almost lets you start over with food, allowing you to take food groups out of your normal rotation and put back in what makes you feel better. But even then, if someone suspects food sensitivities as the culprit behind their bloating, digestive issues, fatigue, or irritability, it may be best to try eliminating just one food at a time as this can be more effective in pinpointing what food you may be sensitive to.

What Are The Drawbacks of Whole30?

Following such a strict diet makes living life hard. It is extremely strict and perpetuates the all-or-nothing mentality.

To give the program some credit, though: The all-or-nothing mentality is intense during the first 30 days, but after you successfully complete those 30 days, the program encourages you to add foods back in one-by-one. Because the program only lasts a month, Whole30’s only real potential benefit for body composition is for short-term weight loss–not long-term weight maintenance or general health, because overall it isn’t a very sustainable way of living. To date, There are no studies on Whole30 specifically as it relates to fat loss, so it’s hard to say it’s good (or not good) for improving body composition.

Whole30 does hold the potential to push those at risk of an eating disorder over the edge. Because the program is so strict, it can cause people to develop fabricated lists of “right” and “wrong” foods — the hallmark of orthorexia nervosa.

What is the right approach for you?

Sustainability is the key to success

A diet that works is one you can sustain. Research shows any diet will do if you stick to it: “Significant weight loss was observed with any low-carbohydrate or low-fat diet,” one study reports. “Weight loss differences between individual named diets were small. This supports the practice of recommending any diet that a patient will adhere to for weight loss.”

Very low-carb diets–like Paleo and Whole 30–are often critiqued by health and medical professionals not because they are ineffective for weight-loss, but because they aren’t sustainable in the long term. U.S. News and World Report keep Whole30 near the bottom of their list for best diets.

By contrast, “lifestyle” diets like the Mediterranean diet are often recommended because they aren’t too strict and focus on living a holistically healthy life. For example, the MedDiet ranked #1 (tied with the DASH diet) as the best diet last year by U.S. News.

The rankings were made after a panel of nationally recognized experts in nutrition, food psychology, diabetes, and heart disease reviewed every diet profile to check for certain categories, including weight loss effectiveness, nutritional completeness, and ease of compliance.

If you’re careful to eat all nutrients and consume enough calories, however, you may find even low-carb diets sustainable long-term. If you can’t stand fish or are allergic to nuts, the Mediterranean diet certainly won’t be sustainable. The key is to honestly assess your preferences and evaluate diets with that knowledge in mind.

It also helps to think about your body composition goals. The first step will be to take a body composition test.

Above all, remember that you know yourself best–so take into account the studies, regimens, and drawbacks presented here to create your health plan!

**Thank you very much InBody USA for your contribution and publishing of this article. For more visit

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