40/30/30 Macros: Pros and Cons

May 13

One of the most popular variations of the macro diet is the 40 30 30 macros program. Some people following a macro diet use this nutrient breakdown as the basis for planning their meals. The popular Zone Diet also adheres to this macronutrient breakdown, so if you sign up for that plan (by purchasing the book or joining the diet plan online), you will also adhere to this macro balance.

On this plan, you consume 40% of your calories from carbohydrates, 30% from protein, and 30% from fat. This plan deviates slightly from guidelines provided by major health organizations, such as the Dietary Guidelines for Americans (DGA). For that reason, you should consider the pros and cons of a 40 30 30 macro plan before going on this diet.

40 30 30 Macros: The Basics

Before we dive into why you may or may not want to follow a 40/30/30 plan, I’ll explain what your diet might look like on this program and how it differs from the guidelines provided by the DGA.

The Zone Diet—or the 40 30 30 plan—reduces the carbs you consume each day so you can consume more protein and more fat. It differs just slightly from the 2020-2025 Dietary Guidelines for Americans, which suggest that you should consume:

10% to 35% of your calories from protein
45% to 65% of your calories from carbohydrates
20% to 35% of your calories from fat

You’ll notice that each macro target on the 40 30 30 plan falls within the guidelines except for carbs. On the 40-30-30 plan, you consume 40% of your calories from carbs, but the DGA suggests consuming at least 45% of your calories from carbs.

So, how does this affect your daily meal plan? You should expect to plan each meal around protein rather than carbs on a 40-30-30 plan. Focusing on protein and dialing back carbs may be challenging for people who consume a standard American diet. For example, rather than filling your plate with pasta in the evening, you might fill your plate with grilled chicken or fish and add a small amount of pasta on the side.

As suggested by The Zone Diet, you should also choose fiber- and nutrient-rich carbs and healthy fats (like foods that contain omega-3 fatty acids). Focusing on whole grains, nuts, seeds, and unprocessed foods (like whole fruits and veggies) will help enhance your overall diet quality. If you don’t already include those foods in your diet, you may have to spend more time planning meals to reach your targets.

👉 Daily Macros Calculator: Get Your Personalized Numbers Instantly 👈

The bottom line is that following a Zone-based or 40-30-30 diet may require a bit more work, especially at the beginning. So, is it worth it? Let’s evaluate the pros and cons.

40-30-30 Macros: Pros

Several clinical studies have shown the advantages of eating a bit more protein and fewer carbs, especially if your goal is weight loss. Here are a few reasons why following a 40/30/30 plan might work for you.

Decreased hunger throughout the day. Eating more protein and (slightly) more fat throughout the day helps promote satiety, or the feeling of fullness. As a result, you may feel less hungry and less inclined to eat. If you want to lose weight, increased satiety may help you stay within your calorie goals. However, if you are a person who eats for reasons other than hunger, like boredom or habit, then you may not notice a significant difference in your total calorie intake throughout the day.
Metabolism support: Consuming more protein each day can help maintain muscle mass, especially during weight loss. It is normal to lose some muscle when you decrease calories to slim down, but muscle tissue burns more calories than fat, so maintaining as much muscle as possible can help support a healthier metabolism.
Focus on healthy fats: A 40-30-30 macro diet doesn’t necessarily require that you choose healthy fats, but many people choose this plan to take advantage of the benefits of consuming unsaturated fats, including polyunsaturated and monounsaturated fatty acids. The diet allows for a more substantial fat intake than many other weight loss plans, so you can enjoy foods like nuts, seeds, olives, and avocados. According to the National Institutes of Health, unsaturated fats in foods like these can help improve your cholesterol levels and possibly even ease inflammation throughout the body.
Improved weight loss results: Clinical studies often associate higher protein diets with better weight loss outcomes. Consuming more protein enhances weight loss for several reasons, including the fact that eating protein requires more work than eating carbs or fat. This is often called the “thermic effect of food” or TEF. Increased satiety and metabolism support (mentioned above) can also make weight loss easier.

40 30 30 Macros: Cons

While a 40/30/30 plan offers several advantages, there are also some drawbacks to adopting this macronutrient breakdown. Consider these cons before starting your diet.

Lacks personalization: One of the greatest benefits of choosing a macro diet is that you can customize your macros based on your goals and lifestyle. There is no single macro ratio that is perfect for everyone - including the 40-30-30 plan. It might work for your coworker, your friend, or an influencer you follow on Instagram, but that doesn’t mean it will work for you. In Macro Diet for Dummies, I walk you through the process of finding your own personalized ratio.
May not provide enough energy: Carbohydrates are your body’s preferred energy source. Typically, we consume more than 40% of our calories from carbs to keep our brains and bodies happy. As mentioned above, most nutrition experts suggest that we get at least 45% of our calories from carbs. Cutting back further than that may lead to fatigue throughout the day. Especially if you are a runner, walker, or regular exerciser, you may need more carbohydrates to fuel your workouts adequately.
Some claims are unsupported. Researchers don’t always agree on the “right” diet for better health or weight loss. So, if you see a headline claiming that a 40-30-30 diet is “backed by science!” you must take it with a grain of salt. Some research may support it, but other studies question the effectiveness of higher-protein eating plans. What many experts agree on, however, is that the best diet for you is the one that is sustainable for the long term. Short-term fixes can backfire and even lead to post-diet weight gain.
Doesn’t guarantee a healthy diet: Like all macro diets, simply balancing macronutrients doesn’t guarantee a nutritious eating plan. If you choose heavily processed foods with added sugars, too much sodium, and few nutrients to support good health, you might lose weight, but you won’t benefit your overall wellness. Like any eating plan, the benefits you gain will depend on the quality of food you put on your plate. Focus on less processed whole grains, fruits, vegetables, lean protein, and plant-based protein to gain the most benefits.

Sample 40 30 30 Diet Plan

To get an idea of whether or not a 40-30-30 diet plan is sustainable for you, you should evaluate a sample meal plan. Ask yourself questions like “is this enough food for me?”, or “will I be able to include my favorite foods?”.

This 40-30-30 meal plan provides three meals and two snacks. It totals 1200 calories with a focus on weight loss. But you may need more calories to lose weight safely. Use the calculator to estimate your numbers. Also, like with any meal plan, you can shift calories around based on your schedule. For example, if you workout in the afternoon, it might be helpful to eat more calories in the morning so you have the energy you need to exercise.

Breakfast (350 calories, 30% protein, 40% carbs, 30% fat)

Oatmeal with Berries and Nuts:

1/2 cup rolled oats (150 calories)
1/4 cup mixed berries (40 calories)
1/4 cup chopped walnuts (160 calories)
1/2 cup unsweetened almond milk (20 calories)

Snack 1 (100 calories, 10% protein, 20% carbs, 70% fat)

1/4 cup guacamole (80 calories)
6 baby carrots (20 calories)

Lunch (400 calories, 40% protein, 40% carbs, 20% fat)

Chicken Salad Sandwich on Whole Wheat Bread:

3 oz grilled chicken breast (120 calories)
1/4 cup chopped celery (5 calories)
1/4 cup chopped red onion (10 calories)
1 tablespoon light mayonnaise (50 calories)
2 slices whole wheat bread (140 calories)
1 cup mixed greens with 1 tablespoon vinaigrette (75 calories)

Snack 2 (100 calories, 20% protein, 70% carbs, 10% fat)

Greek Yogurt with Fruit:

1/2 cup non-fat Greek yogurt (60 calories)
1/2 cup sliced banana (40 calories)

Dinner (250 calories, 40% protein, 30% carbs, 30% fat)

Salmon with Roasted Vegetables:

4 oz baked salmon (150 calories)
1/2 cup roasted broccoli (25 calories)
1/4 cup roasted sweet potato (75 calories)

Total Calories: 1200

Macronutrient Breakdown:

Protein: 30-40%
Carbohydrates: 30-40%
Fat: 20-30%

Is a 40/30/30 Meal Plan Right for You?

A 40-30-30 meal plan works for many, but not for everyone. Before you start this type of diet, ask yourself a few questions:

What is your starting point?

Record your food intake for a week. Then, figure out how many calories in your typical diet come from carbs, fat, and protein. If your starting point varies significantly from a 40/30/30 split, then starting this diet may be too drastic and unsustainable. Instead, make smaller adjustments to your macros and see how you feel from week to week. You may find that your macro sweet spot slightly differs from a 40/30/30 ratio, and that’s okay! Remember, finding a sustainable plan is more effective in the long run than choosing a short-term fix.

Do you need more energy for sustained activity?

Are you an endurance athlete? Do most of your workouts involve sustained activities like swimming, running, walking, cycling, etc? If so, you may need more carbs to fuel your sessions. The International Society of Sports Nutrition suggests that endurance athletes training to improve their performance should consume 5–8 grams of carbohydrates per kilogram of body weight each day. For active individuals (who are not involved in intense training), 3–5 grams per kilogram is recommended.

Are you managing any health conditions?

If you have a medical diagnosis, you should always speak with your healthcare provider or a registered dietitian before changing your diet. There may be specific guidelines for you to follow regarding your macronutrient intake. For example, those with diabetes will need to monitor their carbohydrate intake. People with coronary artery disease may want to be careful about their saturated fat intake. Again, personalization is key.

Remember, despite what you may see in the media, there is no “right” or “wrong” diet. But taking time to make thoughtful decisions about your meal plan can be helpful, regardless of your goals. Check out a copy of Macro Diet for Dummies on Amazon or at your local bookstore to get more information about customizing a diet to meet your needs.

Malia Frey