Weightlifting is a popular form of exercise that focuses on building strength and muscle mass. Many people choose to supplement their weightlifting routines with a high-protein diet to help support muscle growth and recovery. But, what happens if you lift weights and don’t eat enough protein? Let’s take a closer look.

What is Protein?

Protein is an essential nutrient that is necessary for many bodily functions, including muscle growth and repair. When you lift weights, you create tiny tears in your muscle fibers. Your body then repairs these tears, making your muscles stronger and bigger than before. Protein helps to support this process by providing your body with the necessary building blocks to repair and build new muscle tissue.

Protein Nutrition
Protein Nutrition

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How Much Protein Do You Need?

The amount of protein you need depends on your body weight, level of physical activity, and fitness goals. According to the American College of Sports Medicine, individuals who engage in regular weightlifting should consume between 1.2 to 1.7 grams of protein per kilogram body weight per day.

What Happens If You Don’t Eat Enough Protein?

If you regularly lift weights but don’t eat enough protein, your body may struggle to repair and build new muscle tissue. This can lead to a plateau in your progress or even muscle breakdown. Additionally, without enough protein, your body may start to break down other tissues, such as your organs or bones, in order to get the necessary amino acids.

How Can You Ensure You’re Eating Enough Protein?

One of the easiest ways to make sure you’re getting enough protein is to include protein-rich foods in every meal and snack. Good sources of protein include meat, fish, eggs, dairy products, beans, and nuts. You can also consider adding a protein supplement, such as whey protein powder, to your diet.

Monitoring Your Protein Intake

If you’re unsure if you’re getting enough protein, you can monitor your intake by tracking your daily food intake using a food diary or app. Additionally, you can speak with a registered dietitian or nutritionist to help you develop a meal plan that meets your individual needs.

What are the symptoms of not enough protein?

Protein is a crucial macronutrient that plays a role in nearly every biological process in our bodies. Insufficient protein intake over a prolonged period can lead to various symptoms and health issues. Here are some signs and symptoms that may indicate inadequate protein intake:

  1. Muscle Loss: Muscle weakness or muscle wasting is a classic sign of protein deficiency. Without adequate protein, the body might start breaking down muscle tissue for energy.
  2. Skin, Hair, and Nail Problems: Protein insufficiency can manifest in brittle nails, hair loss, and dry, flaky skin. Severe protein malnutrition can lead to edema (swelling) of the skin and a condition called “dermatosis,” characterized by a rash, depigmentation, and hyperkeratosis.
  3. Increased Risk of Bone Fractures: Proteins help maintain bone mass. Inadequate protein can lead to bone density loss, increasing the risk of fractures.
  4. Weakened Immune System: Protein is vital for building and repairing immune cells. A deficiency can weaken the immune system, leading to frequent infections or prolonged recovery times from illness.
  5. Fatigue and Weakness: Protein helps in the formation of enzymes and hormones that regulate metabolism. A lack of protein might lead to feelings of fatigue, lethargy, and overall weakness.
  6. Mood Changes: Amino acids, the building blocks of proteins, are essential for neurotransmitter synthesis. A lack of these amino acids can influence brain function and mood, potentially leading to symptoms like irritability or depression.
  7. Poor Growth in Children: In growing children, protein is crucial for proper growth and development. A deficiency can stunt growth.
  8. Hunger and Increased Appetite: Protein helps in satiety. Without enough protein in your diet, you might find yourself feeling hungry more often or experiencing increased appetite.
  9. Delayed Healing: If cuts, bruises, or other injuries take longer than usual to heal, it might be a sign of inadequate protein intake.
  10. Edema: Severe protein deficiency can lead to fluid accumulation in tissues, especially in the feet, ankles, and legs, causing swelling. This condition is often associated with a severe form of protein malnutrition called kwashiorkor.
  11. Cognitive Impairments: Proteins and their amino acid components play roles in brain function. A deficiency can affect cognition, concentration, and memory.
  12. Weight Loss: Severe protein deficiency can lead to unexplained weight loss, as the body starts to break down its protein stores in muscles and other tissues.

It’s essential to understand that many of these symptoms are nonspecific, meaning they could be related to various other conditions or nutritional deficiencies. If you suspect you’re not getting enough protein or experience any of these symptoms, it’s a good idea to see a healthcare professional or nutritionist for a comprehensive evaluation.

Can you still build muscle if you don’t eat enough protein?

Yes, it is possible to build muscle without consuming large amounts of protein, but protein plays a crucial role in muscle repair and growth. Consuming adequate protein can enhance muscle protein synthesis and facilitate the growth of muscle mass over time. Here are some considerations:

  1. Caloric Surplus: Regardless of protein intake, building muscle typically requires consuming more calories than you burn, i.e., being in a caloric surplus. If you’re eating enough calories to be in a surplus but your protein intake is on the lower side, you can still gain muscle, but the rate and efficiency might be diminished compared to if you consumed optimal amounts of protein.
  2. Amino Acids: Protein is made up of amino acids, which are the building blocks for muscle. While the body can produce some amino acids on its own, there are nine essential amino acids that can only be obtained through the diet. If these aren’t sufficiently supplied, muscle protein synthesis (the process of building muscle) can be hindered.
  3. Protein Quality: All proteins are not equal. Some sources, like animal proteins, are more “complete” than others because they contain all the essential amino acids. If you’re consuming lower quantities of protein, it’s even more critical to prioritize high-quality protein sources.
  4. Training: Resistance training stimulates muscle growth. If you’re training effectively and progressively overloading your muscles, even a suboptimal protein intake can still lead to muscle growth, though perhaps not at the maximal rate.
  5. Adaptation: Over time, if consistently consuming low protein, the body can become more efficient at recycling amino acids. This means the body can get better at reusing existing amino acids to repair and build muscle tissue, but this adaptation has its limits.
  6. Nutrient Timing: While nutrient timing isn’t as crucial as overall daily intake, consuming protein around the time of your workout might enhance muscle protein synthesis slightly. This could be particularly beneficial if overall protein intake is lower.
  7. Age and Individual Variation: Older individuals may need more protein than younger people to stimulate the same level of muscle protein synthesis. There’s also individual variability, meaning some people might fare better on lower protein intakes than others.

While it’s possible to build muscle with less than optimal protein intake, for the best results, it’s recommended to ensure an adequate intake of protein daily. The general recommendation is around 1.2 to 2.2 grams of protein per kilogram of body weight for those engaging in resistance training, but this can vary based on individual needs and circumstances.

Will I lose muscle if I workout but don’t eat enough protein?

If you work out but don’t consume enough protein, you risk not optimizing muscle repair and growth, and in some cases, you could even lose muscle. Here’s why:

  1. Muscle Protein Breakdown and Synthesis: Exercise, especially resistance training, breaks down muscle proteins. After a workout, the body attempts to repair or replace damaged muscle fibers through a cellular process where it fuses muscle fibers together to form new muscle protein strands or myofibrils. This process increases the thickness and number of myofibrils, leading to muscle growth. Protein consumption supports this process by providing the necessary amino acids for muscle protein synthesis.
  2. Negative Nitrogen Balance: Protein contains nitrogen. When you consume adequate protein, you maintain a positive or balanced nitrogen status. If protein intake is too low, especially while working out, the body can enter a negative nitrogen balance, indicating muscle protein breakdown exceeds muscle protein synthesis. Over time, this can lead to muscle loss.
  3. Caloric Intake: Apart from protein, total caloric intake matters. If you’re not eating enough calories overall, the body might use amino acids for energy instead of muscle repair and growth. In a calorie deficit, adequate protein intake becomes even more critical to preserve muscle mass.
  4. Adaptations: Initially, if you start exercising without increasing protein intake, your body might adapt by becoming more efficient at using available protein. However, this adaptation has limits. Over time, especially if workouts are intense, the risk of muscle loss increases without sufficient protein.
  5. Type of Exercise: Endurance exercises, like running or cycling, increase protein requirements to a lesser extent than resistance training. However, if you’re doing a lot of endurance work and not consuming enough protein, you can still risk muscle loss, especially if you’re in a caloric deficit.
  6. Recovery: Inadequate protein can lead to prolonged recovery times, increasing the risk of overtraining and muscle loss.
  7. Catabolic Hormones: Chronic insufficient protein and caloric intake can raise the levels of catabolic hormones, such as cortisol, which promote muscle breakdown.

In summary, while working out with low protein intake might not lead to immediate or significant muscle loss in everyone, it does compromise muscle growth and repair. Over the long term, or under conditions of caloric restriction, the risk of muscle loss increases. To support muscle maintenance and growth, it’s crucial to ensure adequate protein and caloric intake.


In conclusion, if you’re regularly lifting weights, it’s important to make sure you’re eating enough protein to support muscle growth and repair. Without enough protein, your body may struggle to make progress and could even break down other tissues in order to get the necessary amino acids. By including protein-rich foods in your diet and monitoring your intake, you can ensure that you’re getting enough protein to support your fitness goals.