We've all seen it before: the new year arrives, and everyone is committed to losing weight. You go to the gym, and there isn’t a single soul not running their tails off on the treadmill trying to get rid of that stubborn belly fat. While this may lead to initial weight loss, it’s a problematic approach. So, controversially, I'd like to examine the question: is cardio good for weight loss?

The Two Main Types of Cardio

First things first, it’s important to acknowledge that the type of cardio you perform can fall under two categories:

• Steady State Cardio: This involves maintaining a consistent, moderate-intensity level of exercise for an extended period. Common examples include incline walking, jogging, or cycling at a steady pace. This type of cardio aims to keep your heart rate within a specific target zone for an extended duration, promoting endurance and burning calories over time. During this form of cardio, fat is the body's preferred source of fuel

• HIIT (High-Intensity Interval Training): This is a more intense and time-efficient form of cardio, alternating between short bursts of high-intensity exercises and periods of rest or lower-intensity activity. For instance, you might sprint for 30 seconds, followed by 30 seconds of walking, repeating this cycle. This type of workout helps burn calories quickly, temporarily boosts metabolism, and enhances cardiovascular fitness. During these sessions, carbohydrates are the body's preferred source of fuel

Cardio and Metabolic Adaptation

Excessive cardio places stress on the body, and our bodies are highly efficient at adapting to stress. If your goal is to lose weight and the first thing you do is spend an hour a day on the treadmill, it may initially create a calorie deficit, and you'll probably see the scale go down since your body is working to burn more calories than it consumes. But over time, your body adapts to this specific form of stress, and the initial effectiveness in creating a calorie deficit diminishes.

With consistent cardio, your body becomes efficient at conserving energy, meaning your body can perform the same task using less energy, resulting in burning fewer calories. This adaptation leads to a slowdown in your metabolism. This efficiency means that the same amount of cardio that initially led to a calorie deficit might not have the same impact over time. Once your body is "adapted," you might find that seeing further results requires you to increase the amount of cardio you perform. For many, this is a challenge because they already start with such an intense amount.

Unfortunately, this response makes weight loss more challenging. This is because your body learns to operate on fewer calories, meaning it burns less, in turn making it harder to achieve your weight loss goals.

Is Cardio Good for Weight Loss, or Does It Cause Muscle Loss?

Engaging in excessive cardio, particularly prolonged and intense sessions, can lead to the breakdown of muscle tissue for energy. This effect is known as 'catabolism,' which refers to the process of breaking down complex molecules into simpler ones—in this context, the breakdown of muscle tissue.

Losing muscle mass decreases overall strength and fitness and negatively impacts metabolism. Muscle is an 'active tissue,' meaning it requires energy (calories) for maintenance. The less muscle you have, the fewer calories your body burns at rest, making weight loss more difficult. This is why preserving, or even building, muscle should be a top priority during weight loss. Additionally, maintaining muscle mass can improve your overall body composition (the ratio of muscle to fat in your body) and long-term metabolic health

Excessive cardio, regardless of type, can also interfere with your body's ability to recover properly from one training session to another. Our capacity for recovery is limited and exceeding that limit can lead to decreased performance and, once again, the risk of muscle loss.

Cardio and cortisol levels

Excessive cardio routines can also elevate cortisol levels, which is your body's stress hormone, linked with an increase in appetite. As cortisol rises, it can influence your appetite by triggering cravings for sugary and high-fat foods.

This was demonstrated by a study conducted by Epel et al. (2001) investigating the relationship between chronic stress, cortisol levels, and dietary preferences. The researchers observed that individuals experiencing chronic stress displayed a preference for energy-dense foods, particularly those high in sugar and fat, suggesting a potential link between elevated cortisol levels indicative of prolonged stress and altered dietary habits favoring calorie-dense options.

This hormonal response is part of the body's mechanism, where stress would indicate a need for quick and easily accessible energy sources. Consequently, this heightened cortisol-induced appetite can undermine your weight loss efforts, as increased consumption of calorie-dense foods can counteract the calorie deficit created by cardio exercise.

Cardio Makes You Hungry

Extended cardio sessions often trigger hunger by lowering your blood sugar levels, which is important to understand when managing your eating habits post-workout. The body's natural response is to crave quick sustenance after strenuous activity, adding a layer of challenge to your fitness goals. Unfortunately, this can lead to consuming extra calories that may negate the calorie burn achieved during the workout.

It's important to be mindful of what you eat after a workout to avoid undoing the calories you’ve just burned. For example, a 30-minute treadmill run typically burns 300-400 calories for the average person. This effort often increases appetite, but consuming something like a sandwich could easily negate the calorie deficit you worked hard to achieve. It raises an important question: is all that extra cardio truly worth it?

Is Cardio Good for Weight Loss in the Long Run?

Relying solely on cardio for weight loss raises concerns regarding its long-term sustainability. Achieving weight loss through endless high-intensity cardio sessions might be effective initially, but the challenge lies in maintaining such efforts indefinitely. For many, the prospect of continuing intense cardio sessions forever is daunting. Incorporating strength training can provide a more balanced fitness routine, reducing the monotony and potentially increasing metabolic rate, which aids in fat loss over the long term.

A more effective way to use cardio for your weight loss goals is to introduce it strategically towards the end of your journey. This approach is particularly useful for overcoming the inevitable plateaus that occur as your body fat percentage decreases and it becomes harder to shed pounds. While this doesn't mean avoiding cardio entirely, it's beneficial to reserve it for these challenging phases. If you find a type of cardio you truly enjoy and can see yourself maintaining long-term, integrating it consistently into your routine is advisable.

This recommendation is specifically for those who engage in extended cardio sessions in the hope of reaching their dream body. It's important to recognize that such practices may not be sustainable in the long run.

This blog post isn’t meant to discourage cardio. If you enjoy it and can commit long-term, cardio can be a valuable part of your weight loss plan—especially after resistance training. However, if cardio isn’t your preference, you can focus on creating a caloric deficit through diet instead. When fat loss slows in stubborn areas, that’s the perfect time to reintroduce cardio. So, is cardio good for weight loss? Absolutely—but think of it as a strategic tool to use when it’s most effective.