Can You Build Muscle With A Bad Diet? (Our Honest Answer)

While lifting weights and regular exercise contributes to building muscle, eating a proper diet also plays a huge role. In fact, a proper diet can directly impact how successful you are at building muscle.

It will be difficult to build muscle if your diet is lacking in certain nutrients such as essential amino acids. In addition, if you’re undereating, it will be very difficult for your body to put on muscle. Eating processed foods in moderation will not hinder progress if the majority of your diet comes from whole foods.

In this article, I will discuss:

  • What is considered a poor diet for building muscle?
  • Are there valid reasons to have a bad diet when building muscle?
  • 4 major drawbacks of eating a poor diet while bulking
  • 5 things you should do when building muscle

What Is Considered a Poor Diet for Building Muscle?

What is considered a poor diet for building muscle?

In order to determine whether or not you should try to build muscle on a poor diet, you must first understand what a poor diet consists of. There are a few different factors that can create a poor diet while building muscle, such as:

  • Eating an abundance of low-quality processed foods – If you are trying to build muscle but are getting most of your calories from low-quality, highly processed foods, your diet will lack certain essential vitamins and minerals your body needs.
  • Not eating enough protein – Protein is an essential nutrient for building muscle. If your diet does not include enough of it, you will have a much more difficult time building healthy, lean muscle mass.
  • Not eating enough calories – Your body requires a caloric surplus in order to build muscle. If you are not eating enough calories on a consistent basis, this would be considered a poor diet for building muscle.
  • Eating too many calories – While muscle building requires a calorie surplus, if your calorie intake is much higher than the standard 250-500 surplus that is recommended, you will also likely put on excess fat. Although you would still build muscle, excess fat gain is best avoided when you are in a bulking phase.

Related Article: Lean Bulk Macros: How To Calculate (The Proper Way)

Are There Valid Reasons to Have a Bad Diet When Building Muscle?

There may be certain instances where eating a poor diet while trying to build muscle is warranted and will likely not affect your goals. More specifically, if your diet is healthy and you are eating enough the majority of the time, short periods of indulging in more processed food choices will likely not set you back.

For example, going on vacation for a week where your diet and calories are inconsistent and you eat a lot of processed foods will not affect your long-term muscle-building progress as long as you get right back on track when you get home.

Similarly, having a day here or there where your schedule is jam-packed and you are forced to resort to processed food choices while on the go should not affect your progress.

However, if these “busy days” where the quality of your diet is poor become a consistent occurrence, it might be time to address how you can juggle your demanding schedule with eating a healthy diet more efficiently.

For example, if your weekly calendar does not allow you enough time to meal prep healthy foods, it might be worthwhile to invest in a meal prep service to help ease the burden of cooking and help you reach your goals.

You can even try signing up for meal subscription services such as Hello Fresh or Chefs Plate, which would save you the time it takes to grocery shop for healthy recipes.

What Results Can I Expect from Eating a Poor Diet While Trying to Build Muscle?

Although it is still possible to build muscle while eating a poor diet (provided that you are strength training and eating in a calorie surplus), you likely will not experience the same success that you would if the majority of your calories come from whole, unprocessed foods.

Not only that, but if you are eating a poor diet that is low in nutrients while trying to build muscle, you could experience negative health effects that come from not getting enough nutrients. Symptoms such as low energy, unstable blood sugar, and poor digestion are common when eating an abundance of processed foods.

In the section below, I will discuss how a poor diet can affect you while trying to build muscle.

4 Major Drawbacks of Eating a Poor Diet While Bulking

4 major drawbacks of eating a poor diet while bulking

Four drawbacks of eating a poor diet while bulking are:

  • It can lead to a deficiency in certain vitamins and minerals
  • You may not get all of the essential amino acids required to build muscle
  • An inconsistent calorie intake can affect muscle gain and cause excess fat storage
  • A poor diet can cause poor digestion

1. It Can Lead to a Deficiency in Certain Vitamins and Minerals

If you consume most of your calories from low-quality processed foods, you will likely be lacking in many of the essential vitamins and minerals that you would get from eating whole foods.

While vitamin deficiencies tend to develop slowly and over time, if you consistently eat foods void of essential nutrients, you could eventually experience symptoms such as low energy, dizziness, mood changes, and muscle weakness.

The most common vitamin deficiencies seen from eating a highly processed diet are low levels of iron, B vitamins and fat soluble vitamins A,D, E and K. These nutrients are essential for many functions in the body, including having healthy amounts of energy.

2. You May Not Get All of the Essential Amino Acids Required to Build Muscle

Because protein is the most essential nutrient for building muscle, it is crucial that we get enough of it from a variety of sources. This is because protein-rich foods contain essential amino acids that are the body’s building blocks.

Low-quality foods that are highly processed often do not have the essential amino acids that the body needs to build muscle. For this reason, you are better off consuming protein from whole food sources such as meat, poultry, eggs, and dairy products.

3. An Inconsistent Calorie Intake Can Affect Muscle Gain and Cause Excess Fat Storage

An inconsistent calorie intake, whether that be way too many calories or not enough, will ultimately affect how efficient your body is at building muscle.

For example, if you consistently eat below the calorie surplus required for you to put on muscle, your body will not have enough fuel to properly build lean mass.

Similar to this, consuming far too many calories will likely cause excess fat storage during a muscle-building phase. You can easily avoid this if you ensure that you are eating a consistent amount and stay within a healthy calorie surplus of around 250-500 calories above your normal maintenance calories.

4. A Poor Diet Can Cause Poor Digestion

If you constantly eat a poor diet void of foods high in fiber and water content, this will negatively affect your digestion and potentially cause issues such as constipation.

While this may not seem like it would directly impact whether or not you can build muscle, digestive issues such as bloating and constipation can contribute to feelings of sluggishness and low energy and potentially lead to more health issues down the road.

For this reason, it is important to eat a diet full of whole foods rich in fiber, which will help support a healthy digestive system.

You Should Do These 5 Things When Building Muscle

You should do these 5 things when building muscle

If you are trying to build muscle, you should aim to do these 5 things with your diet:

1. Prioritize High-Quality Protein at Each Meal

The number one thing you should focus on if your goal is building muscle is protein intake. Not only do you want to make sure you eat enough protein, but you will also want to make sure it comes from high-quality sources. This makes a difference in whether or not you are getting all of the 9 essential amino acids.

In order to build muscle, around 30-35% of your total daily calories should come from protein. If you eat 2000 calories per day, you would need to eat around 150-175 grams of protein per day to reach your goal.

Good quality protein sources to include in your muscle-building diet include:

  • Meat and poultry (beef, bison, chicken, turkey, pork)
  • Fish (salmon, cod, halibut, mahi-mahi)
  • Eggs and egg whites
  • High protein dairy products (Greek yogurt and cottage cheese)
  • Whey or plant-based protein powder
  • Tofu, lentils, and legumes

2. Eat High-Quality Unprocessed Carbohydrates

Carbohydrates are not only important in the process of muscle building, but they are also your body’s preferred energy source, meaning they are what primarily fuels your workouts. Therefore, you want to fill your diet with high-quality carbs that will keep you feeling full and energized throughout the day.

Good quality carbohydrates to include in your muscle-building diet are:

  • Whole grain bread and pasta
  • Oats
  • Rice
  • Sweet potatoes
  • Regular potatoes
  • Fruit

3. Focus on Fiber Intake to Ensure Healthy Digestion

In order to avoid symptoms such as bloating or constipation that can be brought on by a processed diet, focus on eating most of your calories from unprocessed foods with high fiber content.

Fibrous fruits, vegetables, and nuts will help your digestion and provide you with many nutrients that you won’t find in a processed food diet.

Foods that are high in fiber and other essential nutrients include:

  • Leafy greens
  • Cruciferous vegetables (broccoli, cauliflower)
  • Carrots
  • Celery
  • Beets
  • Berries (blueberries, raspberries, blackberries, strawberries)
  • Apples
  • Nuts and seeds (almonds, cashews, chia seeds, flaxseeds)
  • Beans (chickpeas, black beans, kidney beans)

4. Track Your Calorie Intake to Ensure you are in a Healthy Surplus

If your goal is to build muscle, you need to eat in a healthy calorie surplus for a consistent period (aim for 8-12 weeks) to see results. The best way to do this is to track your calorie intake on a daily basis to make sure you eat enough.

For a calorie tracking app, I recommend MacroFactor. Use this link and enter the code FEASTGOOD when signing up to get an extra week on your free trial (2 weeks total). Cancel any time before your trial ends without being charged.

To determine what a healthy calorie surplus looks like for you, you must first determine your maintenance calories by figuring out your total daily energy expenditure (TDEE). You can easily do this by using an online TDEE calculator like this one here.

Once you have calculated your maintenance calories, you can then decide on a calorie surplus by adding 250-500 calories to your maintenance intake. The combination of eating above your maintenance calories and strength training should result in added muscle on the body over time.

5. Plan Your Food Ahead of Time and Don’t Skip Any Meals

When it comes to any body composition goal, consistency is key. Therefore, if you want to ensure your success in a muscle-building phase, it is best to plan your meals ahead of time.

Meal prepping ahead of time will help to make sure you don’t miss any of your meals. It will also help to ensure you aren’t caught off guard and hungry while on the go, which could lead to you reaching for convenient, processed foods.

Try to get into a routine of meal prepping at the same time every week. For example, if you normally have free time on Sundays, plan your big grocery shop on this day, and allow yourself time to prep your food for the week ahead.

Frequently Asked Questions

Do You Have to Stop Eating Junk Food to Build Muscle?

While you should try to get the majority of your calories from whole, unprocessed foods when trying to build muscle, this doesn’t mean you can’t indulge in junk food once in a while. Try to eat 80-90% of your calories from whole foods while saving around 10-20% of your intake for your favorite processed foods.

Other Muscle Building Resources


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Harshman, S. G., Wons, O., Rogers, M. S., Izquierdo, A. M., Holmes, T. M., Pulumo, R. L., Asanza, E., Eddy, K. T., Misra, M., Micali, N., Lawson, E. A., & Thomas, J. J. (2019). A Diet High in Processed Foods, Total Carbohydrates and Added Sugars, and Low in Vegetables and Protein Is Characteristic of Youth with Avoidant/Restrictive Food Intake Disorder. Nutrients, 11(9), 2013.

Lopez MJ, Mohiuddin SS. Biochemistry, Essential Amino Acids. [Updated 2023 Mar 13]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023 Jan-. Available from:

About The Author

Colby Roy

Colby Roy is a holistic health and nutrition coach. She is certified through Precision Nutrition and has a passion for all things nutrition and healing the body. More specifically, Colby likes to work with clients who want to optimize their gut health and energy levels.