Understanding What is Phase 1 of the high metabolism diet?

October 13, 2025 •

4 min read

According to celebrity nutritionist Haylie Pomroy, the Fast Metabolism Diet cycles foods to trick your metabolism into working faster. The first stage, Phase 1, focuses on unwinding stress and preparing your body for fat burning through high-glycemic, high-carb foods.

Quick Summary

Phase 1 of the Fast Metabolism Diet aims to unwind stress hormones like cortisol by focusing on high-glycemic carbohydrates and lean protein, while avoiding fats. It is a two-day dietary and exercise protocol designed to prepare the body for the more intensive fat-burning phases that follow.

Key Points

Stress Reduction: The primary goal of Phase 1 is to calm the adrenal glands and lower the stress hormone, cortisol.
High-Carb, Low-Fat: Focus on high-glycemic fruits and whole grains while avoiding all fats, including healthy ones.
Moderate Protein: Incorporate moderate amounts of lean protein, such as turkey, beef, and lentils, to support muscle.
Aerobic Exercise: Engage in at least one vigorous cardio session, like running or elliptical, during these two days.
Forbidden Foods: Strictly avoid wheat, corn, soy, dairy, caffeine, alcohol, and refined sugar.
Hydration: Drink plenty of water throughout the day to support metabolic processes.

The Fast Metabolism Diet, often referred to as the 'high metabolism diet,' is a strategic eating plan that cycles through specific food groups over a weekly basis for 28 days. Developed by Haylie Pomroy, the diet aims to keep your body guessing and optimize your metabolic function. It is structured into three distinct phases, each with a different focus, from stress reduction to fat burning. The first stage, Phase 1, is crucial for setting the groundwork and convincing the body it is no longer in 'emergency' mode.

The Foundations of the Fast Metabolism Diet

The Fast Metabolism Diet is not a simple low-calorie plan but rather a method of engaging the body's natural metabolic processes. The overall program includes several core principles:

Meal Timing: Eating 5 times per day, every 3-4 hours, starting within 30 minutes of waking.
Food Cycling: Rotating food groups through three distinct phases to prevent metabolic slowdown.
Food Restrictions: Strict avoidance of wheat, corn, soy, dairy, refined sugar, caffeine, and alcohol.
Hydration: Consuming half of your body weight in ounces of water daily.
Organic Focus: Encouraging organic foods to avoid preservatives and hormones.

What is Phase 1 of the high metabolism diet?

Phase 1 of the Fast Metabolism Diet spans the first two days of the week (typically Monday and Tuesday). Its central objective is to calm the adrenal glands and reduce the stress hormone cortisol. High levels of cortisol can signal the body to store fat, so Phase 1 focuses on foods that help lower it and prepare the body for the weight loss to come. This is achieved by consuming high-glycemic fruits and high-carb, moderate-protein foods, while strictly avoiding fats.

Phase 1 Dietary Guidelines

During these two days, the diet is high in carbohydrates to soothe the adrenal glands and moderate in lean protein to support muscle and satiation. Fats, including oils, avocados, and nuts, are to be avoided. Key food groups for Phase 1 include:

High-Glycemic Fruits: Pears, mangoes, pineapples, oranges, cantaloupe, and kiwi.
High-Carb Whole Grains: Oatmeal, brown rice, quinoa, and brown-rice pasta.
Moderate Lean Protein: Lean beef, turkey breast, lentils, and beans.
Vitamin B & C-Rich Foods: Lentils, oranges, kiwi, and lean beef.
Vegetables: Most vegetables are allowed, especially broccoli, tomatoes, and carrots.

Sample Phase 1 Meal Plan

To give you an idea of what a day on Phase 1 looks like, here is a sample menu:

Breakfast: A bowl of oatmeal topped with mango chunks.
Snack: An orange.
Lunch: Quinoa salad with black beans, bell peppers, and a cilantro-lime dressing (no oil).
Snack: A pear.
Dinner: Grilled chicken breast with a large serving of steamed brown rice and broccoli.

The Role of Exercise in Phase 1

In addition to the diet, Phase 1 includes specific exercise recommendations. The emphasis is on vigorous cardiovascular activity, like running, elliptical training, or a high-intensity interval training (HIIT) workout. This cardio burst helps channel the energy from the high-carb intake and further supports the metabolic kickstart.

What to Expect in Phase 1

For many starting the diet, Phase 1 can feel restrictive due to the exclusion of fats, caffeine, and other common foods. Some might experience initial fatigue as the body adjusts, especially those accustomed to a high-fat diet. However, followers report feeling energized and less stressed after the first two days. The strict adherence is critical to achieve the full effect of the 28-day program.

Comparison of the Fast Metabolism Diet Phases


Feature	Phase 1 (Monday-Tuesday)	Phase 2 (Wednesday-Thursday)	Phase 3 (Friday-Sunday)
Goal	Reduce stress (cortisol), unwind, and calm the adrenal glands.	Unlock stored fat and build muscle.	Unleash the burn; accelerate metabolism and support hormones.
Macros	High-glycemic carbs, moderate protein, no fats.	High protein, non-starchy veggies, low carbs and fats.	Healthy fats, moderate carbs and protein.
Key Foods	Oatmeal, quinoa, brown rice, mangoes, pears, lean beef, lentils.	Turkey, bison, fish, chicken, leafy greens like spinach and kale.	Avocado, olives, nuts, seeds, coconut, moderate grains and fruit.
Forbidden Foods	Fats, caffeine, alcohol, corn, soy, dairy, sugar, wheat.	Grains, fats, fruits, caffeine, alcohol, corn, soy, dairy, sugar, wheat.	Caffeine, alcohol, corn, soy, dairy, sugar, wheat.
Exercise	Intense aerobic exercise (cardio).	Strength training (lifting weights).	Stress-reducing exercise (yoga, massage).
Duration	2 days.	2 days.	3 days.

Conclusion

Phase 1 of the high metabolism diet serves as the body's metabolic reset button. By strategically flooding the system with high-carb, high-glycemic foods while restricting fats, the goal is to calm stress hormones and prime the body for subsequent fat burning. While some of the diet's specific scientific claims have been questioned, its overall focus on whole, unprocessed foods and regular exercise can lead to weight loss and improved nutritional health. As with any significant dietary change, it is always recommended to consult a healthcare professional, especially if you have underlying health conditions. It is a demanding but structured approach for those seeking to kickstart their metabolism and foster healthier eating habits. Learn more about the program at the Fast Metabolism Diet website.

Frequently Asked Questions

The purpose of Phase 1 is to reduce stress hormones, primarily cortisol, by providing the body with high-glycemic carbohydrates and moderate protein, signaling that it is not in a 'starvation' state and preparing it for effective fat burning.

Phase 1 is a two-day phase that typically occurs on Monday and Tuesday, though followers can start their weekly cycle on any day.

Phase 1 emphasizes high-glycemic fruits (e.g., mango, pineapple), high-carb whole grains (e.g., quinoa, oatmeal), and moderate, lean proteins (e.g., turkey, lentils). It is crucial to avoid fats during this phase.

Vigorous aerobic exercise, such as running, using an elliptical trainer, or HIIT, is recommended during Phase 1 to utilize the high-carb intake and boost metabolism.

Fats are prohibited during Phase 1 to encourage the body to use carbohydrates for immediate energy and to focus on calming stress hormones, rather than storing fat.

No, caffeine is one of the strictly prohibited items during Phase 1 and the entire 28-day diet. The plan emphasizes natural foods and avoids stimulants.

While the diet promotes healthy foods and exercise, many of its specific claims, such as controlling blood pH or manipulating metabolism with specific foods, lack solid scientific backing. The weight loss results are more likely due to the emphasis on whole foods and calorie reduction.