What Is the Metabolic Typing Diet?

What Is the Metabolic Typing Diet?

The Metabolic Typing diet centers around the concept that your metabolism—how your body burns food for energy—is unique to you and largely determined by your genetics. The diet suggests that the rate of your metabolism is determined by two inherited factors including the most dominant autonomic nervous system and the rate of cellular oxidation.

The most dominant autonomic nervous system is the energy-burning sympathetic nervous system versus the energy-conserving parasympathetic nervous system.  Meanwhile, the rate of cellular oxidation is how quickly your cells turn food into energy. According to the diet creators, these factors determine your metabolic type—protein type, carbo type, or mixed type. And, your metabolic type determines what types of food you should eat. 

The Metabolic Typing Diet was introduced in 2001 by Trisha Fahey and William Wolcott with the publication of their book “The Metabolic Typing Diet.” The authors claim that eating according to your metabolic type reduces food cravings, helps you reach your ideal weight, and boosts energy.

The 7-Day Diet Plan

There is no set meal pattern for the Metabolic Typing Diet. However, what you eat depends on your metabolic type.

Metabolic Type

There are three different metabolic types—the protein type, the carbo type, and the mixed type. The protein type has a fast metabolism, carb type has a slow metabolism, and mixed type has an average metabolism. People who eat with their metabolic type in mind, will vary their diet based on the speed of their metabolism with protein types need slower digesting foods and carb types need foods that digest quickly. Here is a closer look at each metabolic type.

Protein Type

According to Fahey and Wolcott, protein types have a fast metabolism and need to eat slow-digesting foods like fat and protein. They focus on macronutrient distribution and recommend protein types follow a diet consisting of 45% to 50% protein, 20% fat, and 30% to 35% carbohydrate.

Carbo Type

Carbo types have a slow metabolism and need to eat a diet consisting of foods that digest quickly. This means a diet high in carbs and low in fat and protein with 70% to 80% of calories coming from carbs, 5% to 10% from fat, and 15% to 20% from protein.

Mixed Type

Mixed types have an average metabolism. They don’t burn calories too slowly or too quickly. According to the Metabolic Typing Diet, people with a mixed metabolic type need 40% to 45% of calories from protein, 50% to 55% from carbohydrates, and 10% to 15% from fat.

What You Can Eat

What you eat on the Metabolic Typing Diet depends on your metabolic type. However, each diet type encourages eating more whole foods. 

Protein Focused

Foods high in protein and fat are encouraged for the protein type. The authors of the diet suggest choosing proteins high in purines such as organ meats, red meat, dark-meat poultry, herring, and mussels. Fat should come from eggs, cream, and cheese. Carbs should come from whole grains and vegetables. 

Carbohydrate Focused

Complex carbohydrates like whole grains, fruits, and vegetables are the focus of the carbo-type meal plan. The diet recommends carbo types eat a small serving of a low-purine protein with each meal, such as white-meat poultry, haddock, and flounder. Carbo types can also have low-fat dairy products. 

Mixed Metabolic Types

Mixed types can eat complex carbohydrates, all types of proteins, and an assortment of fats. 

What You Cannot Eat

Though the macronutrient content for each metabolic type differs, each plan includes food options from all of the food groups. However, all three types limit refined carbohydrates and added sugars. 

How to Prepare the Metabolic Typing Diet & Tips

The Metabolic Typing diet is a long-term diet based on your inherited metabolic type. However, your metabolic type may change over time and you may need to adjust your eating plan accordingly.

Though there are no specifics about meal timing, the creators of the Metabolic Typing Diet recommend following each metabolic type as outlined in the book. For example, including high or low-purine protein at each meal. The Metabolic Typing Diet also encourages the use of supplements specific to your metabolic type. 

High- and Low-Purine Proteins

The Metabolic Typing Diet encourages protein at each meal for all metabolic types. However, it distinguishes between high-purine proteins and low-purine proteins.

Purines are chemical compounds your cells use to make DNA and RNA. Meat is a source of purines. According to the authors of The Metabolic Typing Diet, purines in protein foods affect the energy-producing processes in the body. High-purine proteins provide energy for protein types but slow down energy production for carbo types.

Pros of the Metabolic Typing Diet

Most health professionals agree with the basis of the Metabolic Typing Diet that no single diet works for all. However, the strictness of the food plans for the diet types makes it hard to follow long-term.

• Offers customized plans: Proponents of the Metabolic Typing Diet appreciate that their diet type is customized to match their body’s chemistry. The Dietary Guidelines for Americans agree that customization is important when it comes to balanced meal plans. But, the guidelines suggest focusing on food preferences, culture, and budget rather than body chemistry.
• Limits processed foods: The Metabolic Typing Diet recommends all diet types limit refined carbohydrates (white bread, white rice) and sugar. The dietary guidelines also recommend limiting highly processed foods, drinks, and added sugar. Processed foods are inexpensive sources of energy and nutrients and are linked to health problems like type 2 diabetes and obesity. Diets high in processed foods increase calorie intake and weight gain.

Cons of the Metabolic Typing Diet

The Metabolic Typing Diet uses a lot of science to explain how the plan works. Unfortunately, research to support these claims is limited. 

• Lacks evidence: Research for the Metabolic Typing Diet is sparse. One small pilot study published in 2008 found that the questionnaire the diet uses to determine metabolic type may not accurately reflect a person’s actual metabolic processing. However, current research suggests that people may benefit from diets that take into consideration their unique metabolic phenotype, a concept known as metabotyping. Researchers hypothesize that people at risk for certain diseases have a distinct metabotype and may need more personalized nutrition plans that address their unique metabolic needs, such as a diet high in fermentable fibers ― prebiotics — for people at high risk of heart disease. Overall, more research is needed.
• Tends to be restrictive: The authors of The Metabolic Typing diet recommend you follow your diet type for life. However, any diet that severely limits specific macronutrients or food groups may lead to nutrient deficiencies. Additionally, restrictive diets are hard to follow long-term. 
• Includes foods high in saturated fat: The protein type diet encourages high-fat meats, which are also high in saturated fat. Eating animal products that are high in saturated fat may increase your bad cholesterol and your risk of heart disease.

Is the Metabolic Typing Diet a Healthy Choice for You?

The dietary guidelines recommend eating a balanced and varied diet that includes nutrient-rich foods and beverages from all the food groups. The core elements of a balanced eating plan should include:

• Vegetables of all types
• Fruits
• Grains, with half coming from whole grains
• Low-fat dairy products or plant-based alternative
• Nutrient-rich protein foods
• Oils 

Though the current guidelines provide macronutrient ratios, the recommendations focus on nutrient density rather than the macronutrient distribution of your diet. Current guidelines provide broad recommendations for macronutrient needs: 10% to 35% of calories from protein, 20% to 35% from fat, and 45% to 65% from carbohydrates.

Macronutrient distribution is an important element of The Metabolic Typing Diet. However, none of the metabolic types fit the recommendations from the dietary guidelines. The protein and mixed types are higher in protein and the carbo type is higher in carbs and lower in protein. 

A Word From Verywell

The Metabolic Typing Diet suggests the type of foods you eat affects your health, weight, and energy. While this is true, the metabolic types and the associated meal plans recommended by the Metabolic Typing Diet may not be right for you. Before making any major changes to your diet, consult with your primary care provider or a registered dietitian for guidance. They can customize a balanced meal plan that fits your goals and needs.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.