Greater energy, balanced blood sugar, optimal digestion, and long-term health are just a few of the benefits of eating a healthy, balanced diet. But while the advice to “eat healthy” may sound simple, the constant noise about what you should or shouldn’t eat can feel overwhelming and confusing. Should you go low-carb? What about plant-based or keto diets? With so much conflicting information out there, it’s easy to feel lost. Fortunately, a simple visual guide called “the rule of thirds” can make healthy eating feel much more manageable.
The “rule of thirds” is an effective visual strategy for creating balanced, healthy, and satisfying meals. As a Registered Dietitian, I understand the importance of simplicity and ease when it comes to nutrition, and that’s exactly what this approach offers.
What Is the Rule of Thirds?
The rule of thirds is simple—divide your plate into three parts:
- Protein
- Carbohydrates
- Non-starchy vegetables
In contrast with the USDA MyPlate visual, the rule of thirds simplifies a healthy plate even further. It also eliminates the pressure of counting calories or macros. Simply fill ⅓ Of your plate with protein, ⅓ carbohydrates, and ⅓ non-starchy vegetables. Below is a deep dive into each section of a healthy plate.
The Three Sections on the Plate Explained
1. Protein (1/3 of the plate)
Protein is an integral component of a healthy meal. This essential macronutrient is made up of amino acids, which are the building blocks for muscle, skin, hair, organs, and enzymes. Protein helps build and maintain musclebuild and maintain muscle, repair tissue, build and transport hormones and enzymes, and support immune function. When included in your diet it also aids in satiation, eliminating those after meal cravings. Below are some examples of high quality lean proteins to include in your meals:
- Eggs
- Yogurt
- Chicken
- Fish
- Beef
- Nuts
- Seeds
- Beans
- Tofu
2. Carbohydrates (1/3 of the plate)
Carbohydrates are the body’s main fuel source. This macronutrient breaks down into glucose to fuel the brain, muscles, and nervous system. It’s also the primary fuel source during high-intensity exercise. Consuming carbohydrates supports focus, mental clarity, mood, and memory, as your brain requires glucose for optimal performance. Most carbohydrate sources also provide fiber, which supports digestion, satiety, and helps manage blood sugar levels and lower cholesterol. Here are a few examples of quality sources of carbohydrates:
- Fruits
- Vegetables
- Whole grains
- Legumes (beans, lentils, chickpeas, peas, soybeans, peanuts)
3. Non-Starchy Vegetables (1/3 of the plate)
Vegetables are packed with a host of vitamins, minerals, fiber, and antioxidants. They also add volume to meals, which can help you feel fuller for less calories. Its important to include a variety of vegetables to obtain all different nutrients in your diet. Think of choosing different colored vegetables in your grocery list every week. Here are examples of non-starchy vegetables.
- Leafy greens (spinach, kale, Swiss chard)
- Bell peppers
- Eggplant
- Zucchini
- Broccoli
- Cauliflower
- Cucumbers
- Mushrooms
- Carrots
- Green beans
“Rule of Thirds” in Real Meals
When assembling a healthy and balanced meal with the “rule of thirds”, simply consider similar portions of protein, carbs, and non-starchy vegetables. Here are some examples for each meal:
Breakfast
- Eggs (protein), sautéed spinach and peppers (vegetable), and whole wheat toast (carbs).
- Smoothie made with protein powder or Greek yogurt (protein), leafy greens (vegetable), and berries (carbs) or beans (they add a boost of fiber without altering the flavor).
- Chia seed pudding or Greek yogurt (protein) with fruit (carbs) and almond butter.
*if you’re enjoying a sweeter breakfast such as a Greek yogurt bowl, it’s okay to save your non-starchy vegetables for lunch or dinner. Remember it’s all about balance and not an all or nothing approach.
Lunch
- Salad with leafy greens (vegetable), grilled chicken (protein), and homemade croutons (carbs).
- Sandwich made with whole wheat bread (carbs), canned tuna (protein), and lettuce and tomato (vegetable).
- Baked sweet potato (carbs), topped with black beans (protein), and mixed vegetables like tomato, green onion, and peppers (vegetables).
Dinner
- Chickpea or lentil pasta (carbs) with sautéed mushroom and spinach (vegetables), and turkey meatballs (protein)
- Salmon (protein), with brown rice or quinoa (carbs), and roasted asparagus (vegetable)
Note: the rule of thirds doesn’t mention including fats in your meal, but these are an important macronutrient to include in your diet. Fats support nutrient absorption, hormone production, satiety, and provide essential omega 3 and 6 fats that support heart health, brain health, and development. Since fat is a calorie-dense food, it should be consumed in smaller portions—think of fat as a condiment. Here are some examples on how to include fats in your meals.
- 1 ounce of nuts or nut butter added to Greek yogurt, oatmeal, or on top of toast
- ½ an avocado added to eggs, a sandwich, or a salad
- 1 Tbsp of hemp or flaxseeds added to a smoothie
- 1 Tbsp of olive oil drizzled over a salad
Flexibility & Real-Life Use
As mentioned above, not every single meal may include every component. For example, a bowl of oatmeal or Greek yogurt tastes great paired with fruit and granola, but this meal might not include vegetables. Be sure to build flexibility and balance into your eating style.
The ”rule of thirds” visual is a great learning tool for kids too. Let your kids help prepare meals and ask them if all of the 3 components are included in the meal. If you’re missing one, you can teach your kids how to include all 3.
Building a balanced plate is essential for getting the nutrients you need, but food alone is only part of the equation. Mindful eating is equally important—it can help improve digestion, enhance nutrient absorption, and promote feelings of fullness, all of which can help prevent overeating.
The rule of thirds is a simple visual reminder on how to assemble a balanced and healthy meal. This guide helps ensure you consume all essential macronutrients your body needs for optimal health and energy with a simplified approach. Try including all 3 components at your next meal!