What happens if I don't eat enough when working out?

Author: Monroe Sipes IV  |  Last update: Wednesday, April 16, 2025

Studies suggest that eating or drinking carbohydrates before exercise can help you do better during your workout. And the carbohydrates may allow you to work out for a longer time or at a higher intensity. If you don't eat, you might feel slow-moving or lightheaded when you exercise.

What happens if you exercise but don't eat enough?

Exercising without eating well can have various consequences, both short-term and long-term. Exercising without proper nutrition can hinder your performance, slow down recovery, lead to muscle loss, weaken your immune system, and make it challenging to manage your weight effectively.

What happens if you exercise a lot and eat less?

Yes, eating less with a low-calorie diet puts you on the fast track to weight loss—and an intense exercise routine leads to increased metabolism and decreased body fat. In reality, a crash diet and overzealous exercise routine can be hard to maintain which may lead to more weight gain in the future.

What happens if you work out a lot but don't eat enough protein?

In the absence of enough amino acids, the body will breakdown existing muscles to get amino acids, which is known as muscle catabolism and results in loss of muscle mass. Not consuming enough protein after a workout will result in hindered muscle recovery, muscle growth and repair, and loss of muscle mass.

Does working out work if you don't eat healthy?

Yes, you can still see results from workouts without following a strict diet, but your progress may be slower or inconsistent. Exercise alone can improve strength, endurance, and overall fitness, but nutrition plays a crucial role in muscle growth, fat loss, and energy levels.

The Effects of Under-eating & Muscle Growth

What happens if you exercise a lot but eat unhealthy?

Whether you work out longer or at a higher intensity, exercise can't completely reverse the effects of a bad diet, expert say. There's also an increased risk for premature death if you exercise but neglect healthy eating.

Is it bad if I workout without eating?

Is Working Out On an Empty Stomach Bad for You? According to Roper, fasted exercise is generally safe for most people, but it may lead to side effects. “Because blood glucose gets depleted during fasting cardio, you can experience some side effects including lightheadedness and dizziness,” she said.

Will I lose my muscle if I don't eat enough protein?

When on a weight loss journey, lack of protein is a huge culprit of muscle loss. “Our bodies don't store protein like other nutrients, so it's important to eat the right amount every day,” says Kate. “Everybody is different and will have different protein requirements.

What might the 5 signs of a protein deficiency be?

Top 10 Signs You Might Be Protein Deficient
  • Weakness and Fatigue. ...
  • Hair Loss and Brittle Nails. ...
  • Frequent Illness and Slow Healing. ...
  • Swelling (Edema) ...
  • Cravings and Increased Appetite. ...
  • Muscle Loss and Joint Pain. ...
  • Mood Changes and Mental Fog. ...
  • Skin Problems.

Can I build muscle in a calorie deficit?

But is it possible to build muscle while in a caloric deficit? The short answer is yes, but it's not as straightforward as it might seem. Let's explore how your body builds muscle when you're eating fewer calories than you burn, and how tools like 3D body scanscan help track your progress.

Does your body hold onto fat if you don't eat enough?

Your Metabolism Will Slow Down to Store Fat

It kicks in to preserve and store fat for future energy.

What is considered a crash diet?

A very-low-calorie diet (VLCD), also known as semistarvation diet and crash diet, is a type of diet with very or extremely low daily food energy consumption. VLCDs are defined as a diet of 800 kilocalories (3,300 kJ) per day or less.

Can you gain weight from not eating enough and exercising too much?

Eating too few calories can cause your metabolic rate to slow down, meaning you may gain weight more easily. Your body requires energy when you walk, work out, think, breathe, just about everything else!

What happens if you eat very little and exercise a lot?

In other words, in order to conserve energy and direct calories to necessary functions for survival, your body resorts to burning fewer calories, even as you're exercising regularly and intensely. This means you will hold onto body fat despite eating a low-calorie diet and training hard.

What is the best time to work out?

Your body uses resources more efficiently during evening workouts, allowing you to sustain energy levels and perform at your best. Quickened reaction time during the late afternoon and evening also makes it an ideal time for exercises that require speed, agility, or high-intensity intervals.

Will I lose muscle if I overtrain?

The physiology of overtraining

Liz Au, FITWELL coordinator at UCLA Recreation, said the lack of a sufficient rest gap between exercise bouts can lead to overtraining and possible muscle breakdown, depending on the individual and the intensity of the exercise.

What happens if you lift weights but don't eat enough protein?

Lifting and doing strength training without adequate nutrition, especially without enough protein, can actually lead to loss of muscle tissue. Furthermore, if you aren't eating right you won't have the energy to do the workouts that lead to muscle gain.

How can I tell if my protein is low?

What are the symptoms of low protein in blood?
  1. Brittle hair, hair loss and loss of hair pigment.
  2. Dry skin, rashes and sores.
  3. Edema (fluid buildup) in the stomach or lower limbs.
  4. Fatigue.
  5. Frequent infections.
  6. Itchy skin (pruritus)
  7. Jaundice.

What happens if I eat a lot of protein but don't work out?

You can't build muscle without the exercise to go with it. The body can't store protein, so once its needs are met, any extra protein is used for energy or stored as fat. Excess calories from any source will be stored as fat in the body.

Does your body burn fat or muscle first when starving?

"A person who is attempting to lose weight by not eating may lose weight in muscle first before fat," he says. How does that happen? Well, the body likes to go for carbs (glucose) for energy first.

Why am I gaining weight on a high protein diet?

If you consume more protein but don't work out, you're still likely to gain weight due to increased calorie intake. However, the resulting weight gain is likely due to fat vs. added muscle mass. More muscle mass adds to overall body weight, and muscle is denser than fat.

What happens if you workout but don't eat anything?

If you don't eat, you might feel slow-moving or lightheaded when you exercise. If you plan to exercise within an hour after breakfast, eat a light meal. Or have a sports drink. Focus on carbohydrates for the most energy.

Is it better to drink a protein shake before or after a workout?

The short answer: Many experts suggest having protein after a workout to build muscle mass. But preworkout or postworkout protein may help. Strenuous exercise creates microtears in the muscles. After a workout, your body repairs the damage using amino acids from dietary protein.

Is it bad to workout every day?

Simply put, the more you exercise, the greater your risk of getting hurt. That's just math. But it's more than that. Working out every day—especially engaging in the same types of workouts that target the same muscle groups—means you're stressing your muscles and joints and not giving them time to rest and recover.

Previous article
What is the best haircut for overweight faces female?
Next article
Is honey good for dehydrated skin?