What Happens If You Work Out But Don't Eat Healthily?


Are you aware that an unhealthy diet can significantly reduce your chances of achieving your fitness goals even if you have been rigorously working out in the gym? Have you been going to the gym consistently, but your bad eating habits keep getting in the way? Do you struggle to avoid sugary drinks and junk food? Or do you struggle to eat enough because your appetite isn't big enough? It can be harmful if you consume either too few or too many calories, or the proper number of calories while choosing unhealthy foods and exercising.

No matter how hard you work out, you will never be able to burn off a poor diet. Neither food nor exercise will be sufficient on their own and will need to be supported by the other.

Important nutrients for working out

A balanced diet is essential for proper body function, and it gets even more crucial as you routinely engage in physical activity. While eating the appropriate amount of calories is necessary, macronutrients in the diet are also crucial for weight loss and muscle growth. The main components of your food and those that the body needs in large quantities, specifically proteins, lipids, and carbohydrates, are referred to as macronutrients. When on a diet, it is especially crucial to optimise your macronutrient consumption as per the recommendation of sports nutritionists because it has an impact on your lean mass, strength, energy, and performance.


The building blocks of tissues, bones, muscles, cartilage, skin, hormones, and enzymes are proteins, which are made up of smaller units called amino acids. They are essential for the body's processes of growth, repair, and upkeep. Everybody needs protein, but those who exercise and work out need even more since activity causes microtears in the body's tissues and causes structural damage that needs protein to be repaired. It is crucial to regulate protein intake.

Strenuous exercise increases the rate of muscle protein synthesis and breakdown so a protein-rich pre- and post-workout snack is essential for athletes and fitness enthusiasts, in addition to a healthy, balanced diet. The Reference Nutrient Intake (RNI) for inactive, average-weight people is 0.75 grams of protein per kilogram of body weight per day, according to the British Nutrition Foundation.1 1.2 to 2.0 g of protein per kg of body weight per day from protein-rich dietary sources is what the American College of Sports Medicine (ACSM) advises for people who regularly exercise.

Lean meat,   chicken, fish, dairy products, and eggs are healthier sources of protein for building muscle mass than protein powders and supplements, which are nevertheless accessible.


Do you frequently become exhausted shortly after beginning your workout? Or do you frequently crave and feel hungry even after eating enough? There's a potential that your diet is deficient in fats.

For sports and fitness enthusiasts, in particular, fats are frequently portrayed as harmful substances, and their significance is frequently understated. Along with carbohydrates, they are vital as fuel because they support a variety of biochemical processes within the body and are involved in the synthesis and maintenance of numerous vital parts. The body typically uses carbohydrates as fuel for exercise, but low-intensity, long-duration workouts require the utilisation of fat as fuel, thus a diet low in fats will soon wear you out and reduce the length of your workouts.

As crucial as fats are, it's also critical to choose your fats carefully and mostly rely on healthy fats. Avoid trans fats like margarine, deep-fried foods, and excessive amounts of hydrogenated oils and replace with healthy fat sources such as avocados, nuts, nut butter, fatty fish, and maize, soy, peanut, and sunflower oils, which are rich in omega-3 and omega-6 fatty acids.


The most important components of a diet are carbohydrates because they provide the energy for all physical processes. This is especially true for people who regularly engage in high-intensity exercise. For people who engage in a lot of exercise, it's critical to maintain a high carbohydrate diet to power their workouts.

A lack of carbs to fuel exercises and other body functions results in the breakdown of lean muscles for energy, therefore, eating enough carbohydrates is essential if you want to boost your endurance and stamina and prevent muscle loss. One of the main justifications for the importance of carbohydrates is the fact that they also provide the brain with fuel.

It is equally crucial to ensure that your diet includes good carbohydrates like whole grains, oatmeals, and sweet potatoes as these are complex carbohydrates that keep you full for longer.

Does regular exercise matter if you don't eat healthily?

Exercise is essential to lose stubborn fat and preserve lean muscle mass. It is also a habit that promotes health in the long run because it helps keep the heart healthy, supports stronger muscles and bones, boosts metabolism, and helps with weight control. But would consistent exercise make a difference if you continued to eat junk food and consume insufficient macro- and micronutrients? The short answer is no.

Exercise, despite its numerous advantages, will not help you lose weight if you don't keep track of your calories and macros by eating a balanced diet. Depending on weight, activity level, and a host of other factors, such as whether someone is working out to lose weight, maintenance, or weight gain, each person's notion of healthy eating will differ.

One of the findings of a single-blind study from the University of Bangor which observed 70 women with different BMIs for exercise trials, identified that regular exercise is beneficial for health promotion but has no benefits for weight loss if it is not accompanied by healthy eating habits.3

Preventing benefits of exercise

Even after intense training, it is disheartening to watch the hours spent in the gym go to waste due to a poor diet, which masks the effects of exercise.

Gaining lean muscle

Increasing muscle mass is the preferred benchmark for fitness for the majority of athletes and fitness enthusiasts. Exercise promotes the growth of lean muscle mass because it causes the body's fat reserves to be replenished by the expanding muscle. Gaining lean muscle is advocated for a number of reasons, one of which is that it raises basal metabolic rate, which in turn speeds up metabolism and helps one lose weight even while at rest.

Although exercise helps build lean muscle, a poor diet can cause muscle loss. Poor nutrition, especially a lack of sufficient protein in the diet, causes the muscles to break down for energy, preventing the growth of lean muscle and depleting the body's already existing lean muscle stores.

Improving mood

Regular exercise has a positive impact on mental health and helps regulate mood and emotions because it increases endorphin production.4 But have you ever noticed that following a workout, you become progressively irritable? Your poor dietary decisions are to blame. It's likely that when you consume fewer calories and deplete them through exercise, your endorphin levels will drop precipitously, which will worsen your mood rather than lift it.

Fat loss

When your body is in a caloric deficit, either from eating fewer calories than you burn or from burning more calories than you take in, body fat loss takes place. Even with a strict exercise regimen, the main causes of fat retention in the diet are junk and processed foods. When you eat a diet rich in whole, nutritious foods, you stay satisfied for longer and are less likely to reach for sugary snacks. It's likely that exercising will make someone who consumes an unhealthy diet can set off a vicious circle of binge eating.

Risks of poor diet

The long-lasting impacts of bad dietary choices can predispose you to a variety of deficiencies, physical and mental illnesses, and negatively impact your immune system and energy levels.5

Vitamin Deficiencies

A balanced diet includes the basic macronutrients, micronutrients, and minerals that the body needs to function properly and to replenish its supply of all other needed nutrients. People who do not eat well are more likely to suffer from a variety of nutritional deficiencies, including a lack of vitamin B complex, notably vitamin B12, as well as deficits in vitamin C, A, and D. Anaemia, poor wound healing, frequent muscular cramps, a decline in bone density, and a subpar immune system are all symptoms of vitamin and mineral deficiencies. It also increases inflammation in the body leading to a high incidence of injuries.

Muscle fatigue and low energy

There is a substantial likelihood that you will frequently feel exhausted and low on energy regardless of whether you follow a diet low in calories or high in sugary foods. Even the most comfortable sleep won't be able to eliminate the exhaustion and replenish your energy levels because it is the result of a poor diet. Your physical and mental performance will suffer over time due to a poor diet, and your recuperation time after working out will also be prolonged.

Anaemia, a reduction in the number of red blood cells typically brought on by a low intake of dietary iron, is the main cause of fatigue and low energy levels in people with poor nutrition and is the outcome of long-term poor dietary choices. 


Research shows that even high levels of exercise fall short of reducing the hazards associated with poor food choices, particularly when it comes to mortality risk. A balanced diet and exercise work hand in hand, indicating that a healthy diet cannot compensate for insufficient exercise and that high levels of physical activity cannot repair the harm caused by unhealthy eating habits.


  1. Protein - British Nutrition Foundation [Internet]. Nutrition.org.uk. 2022 [cited 26 August 2022]. Available from: https://www.nutrition.org.uk/healthy-sustainable-diets/protein/
  2. Nutrition and athletic performance. Medicine & Science in Sports & Exercise [Internet]. 2016 Mar [cited 2022 Aug 26];48(3):543–68. Available from: https://journals.lww.com/acsm-msse/Fulltext/2016/03000/Nutrition_and_Athletic_Performance.25.aspx
  3. Jackson M, Fatahi F, Alabduljader K, Jelleyman C, Moore JP, Kubis HP. Exercise training and weight loss, not always a happy marriage: single blind exercise trials in females with diverse BMI. Appl Physiol Nutr Metab [Internet]. 2018 Apr [cited 2022 Aug 26];43(4):363–70. Available from: https://cdnsciencepub.com/doi/abs/10.1139/apnm-2017-0577
  4. More evidence that exercise can boost mood [Internet]. Harvard Health. 2019 [cited 2022 Aug 27]. Available from: https://www.health.harvard.edu/mind-and-mood/more-evidence-that-exercise-can-boost-mood 
  5. Ding D, Buskirk JV, Nguyen B, Stamatakis E, Elbarbary M, Veronese N, et al. Physical activity, diet quality and all-cause cardiovascular disease and cancer mortality: A prospective study of 346 627 UK Biobank participants. Br J Sports Med [Internet]. 2022 Oct 1 [cited 2022 Aug 26];56(20):1148–56. Available from: https://bjsm.bmj.com/content/early/2022/07/08/bjsports-2021-105195
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Sidra Irfan

Bachelors of Dental Surgery, Dentistry, Lahore Medical & Dental College, Pakistan

Sidra is a general dentist who enjoys writing in general but particularly enjoys compiling health tech innovation and patient awareness material. She is an equal healthcare access advocate who is currently engaged in research and public health. She also works as a medical, health, and wellness SEO content writer.

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