What Foods Are Allowed in Phase 1 of the Atkins Diet?

October 27, 2025 •

3 min read

Over 50 million people have tried the Atkins diet, a plan that starts with a restrictive, very low-carb phase to kickstart weight loss. So, what foods are allowed in Phase 1 of the Atkins diet during this crucial induction period? This phase focuses on specific food groups to shift your body into a fat-burning state.

Quick Summary

A guide detailing the specific food groups and acceptable choices for Phase 1 of the Atkins diet, including meats, poultry, fish, eggs, cheese, and low-carb vegetables. Learn about the restrictions on carbs, fruits, and starches.

Key Points

Limited Net Carbs: Phase 1 restricts daily net carbohydrates to 20 grams, with 12 to 15 grams sourced specifically from low-carb foundation vegetables.
High Protein Intake: Un-breaded meats, poultry, fish, and eggs are core components, providing satiety and supporting muscle mass.
Healthy Fats are Encouraged: Butter, olive oil, avocado, and mayonnaise (without added sugar) are allowed and do not need to be restricted.
Specific Vegetable Choices: Focus on leafy greens and other low-starch vegetables like broccoli, asparagus, and bell peppers.
Avoid Sugars and Starches: High-carb foods like grains, most fruits, legumes, and starchy vegetables are off-limits during this induction period.
Hydration is Essential: Drinking ample water, along with clear broths and some diet beverages, is recommended to prevent dehydration.
Strict Adherence is Crucial: Success in Phase 1 relies on carefully following the approved food list to trigger ketosis and jumpstart weight loss.

The Core Principles of Atkins Phase 1

Phase 1, often called the Induction phase, is the most restrictive part of the Atkins diet, typically lasting for at least two weeks. During this time, your daily net carbohydrate intake is limited to 20 grams, with 12 to 15 of those grams coming specifically from 'foundation vegetables'. The primary goal is to shift your body's metabolism from burning carbohydrates for fuel to burning stored fat, a process known as ketosis. To achieve this, the diet emphasizes protein, healthy fats, and specific non-starchy vegetables.

Meats, Poultry, and Fish

Protein is a cornerstone of the Phase 1 menu, providing satiety and helping to preserve lean muscle mass. You can enjoy a wide variety of these foods, but must be careful to avoid those with sugary marinades, breading, or added nitrates. Options include:

Beef: Steaks, roasts, ground beef.
Pork: Chops, tenderloin, bacon (check for sugar curing).
Poultry: Chicken (without skin), turkey, duck.
Lamb and Veal: Chops, roasts, cutlets.
Fatty Fish: Salmon, mackerel, sardines, trout.
White Fish: Flounder, cod, sole, tuna.
Shellfish: Shrimp, crab, lobster, clams (limit mussels and oysters due to higher carb content).

Eggs, Cheese, and Dairy

Eggs are a versatile, nutrient-dense, and carb-free protein source, making them a staple in Phase 1. Cheese is also permitted, though in moderation, as it does contain some carbohydrates. You should aim for no more than 3 to 4 ounces of hard, firm, or aged cheeses daily. Soft cheeses and yogurt are typically not included until later phases. Acceptable cheese options include cheddar, Swiss, mozzarella, and feta. Cream (heavy or light) and a small amount of sour cream are also allowed.

Foundation Vegetables

Vegetables provide essential fiber and nutrients, and in Phase 1, 12 to 15 grams of your daily net carbs must come from these 'foundation vegetables'. Starchy vegetables like potatoes and corn are prohibited. The focus is on leafy greens and other low-carb choices, such as:

Salad Greens: Romaine, iceberg, spinach, arugula.
Cruciferous Vegetables: Broccoli, cauliflower, Brussels sprouts.
Other Low-Carb Veggies: Asparagus, celery, bell peppers, cucumbers, mushrooms, zucchini, snow peas, collard greens.

Healthy Fats and Oils

Fat is not restricted in Phase 1 of the Atkins diet. It is essential for satiety and flavor. This includes fats from meats and fish, as well as added fats like:

Butter
Mayonnaise (with no added sugar)
Extra virgin olive oil
Avocado oil
Vegetable oils like canola and grape seed (cold-pressed is preferred)
Avocado and olives

The Importance of Hydration and Condiments

Drinking plenty of water is crucial to support weight loss and prevent dehydration, especially during the initial water-weight loss. In addition to water, clear broths, herbal teas (without added fruit sugars), and diet sodas (checking carb counts) are allowed. Condiments should be chosen carefully, focusing on those with no added sugar, such as certain salad dressings, herbs, and spices.

Comparison of Atkins Phase 1 vs. Typical Ketogenic Diet


Feature	Atkins Diet Phase 1	Standard Ketogenic Diet
Net Carbs	Generally limited to 20g/day, with specific foundation veggie allowance.	Typically 20-50g/day, with less specific rules on carb sourcing.
Macronutrient Balance	Emphasis on protein and healthy fats, with controlled low-carb vegetables.	Focuses more on very high fat intake, with moderate protein and very low carbs.
Progression	Part of a four-phase plan that gradually reintroduces carbs.	Often followed long-term or cycled, without the same structured progression.
Duration	A fixed induction period of at least two weeks.	Can vary depending on individual goals and is not always time-bound.

Conclusion: Navigating Phase 1 for Success

Understanding what foods are allowed in Phase 1 of the Atkins diet is the first step toward achieving your weight loss goals with this plan. By sticking to the list of approved proteins, fats, and low-carb vegetables, and carefully monitoring your net carb intake, you can successfully navigate this induction period. This approach is designed to trigger ketosis and kickstart your weight loss journey, providing a strong foundation for the subsequent phases. Always remember to stay hydrated, read labels carefully to avoid hidden sugars, and consult a healthcare provider before starting any new diet plan. The structure and specific food lists are key to making this phase effective and manageable. For more detailed information, consult the official Atkins resources.

Frequently Asked Questions

Phase 1, also known as the Induction phase, typically lasts for a minimum of two weeks. However, individuals can extend this phase if they have significant weight to lose or wish for a faster start to their weight loss journey.

In Phase 1 of the Atkins diet, you are limited to consuming 20 grams of net carbs per day. Of this amount, 12 to 15 grams should come from low-carb foundation vegetables.

Yes, some cheeses are allowed in moderation during Phase 1. You should limit your intake to 3 to 4 ounces per day and stick to hard, aged, and firm cheeses like cheddar, Swiss, and feta.

No, most fruits are not permitted during Phase 1 because they are high in sugar. Exceptions include avocado and olives, which are considered fruits but are high in fat and low in net carbs.

In addition to water, permitted beverages include clear broth, herbal tea without added fruit sugars, coffee and tea (regular or decaf), and diet soda, though it's important to check labels for hidden carbs.

The purpose of Phase 1 is to jumpstart weight loss by inducing a metabolic state called ketosis. During ketosis, the body burns stored fat for energy instead of relying on carbohydrates.

No, nuts and seeds are generally not allowed during Phase 1 due to their carbohydrate content. They are typically reintroduced in later phases of the diet.