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Is Cardio Making You Fat?

By May 8, 2013December 30th, 2018Uncategorized



Is Cardio Making You Fat?

I love exercise for so many reasons. For me, it boosts my soul and makes me happy. I love my morning run in the country…seeing deer, the silence, the emotion of gratitude… It took me years to enjoy running. When I first started, I remember aiming for 1/2 mile and that was tough. Now I run every morning without hardship and I do it because I love it, not for weight loss.

I did however sign up for a marathon 6 years ago for weight loss and guess what happened? I GAINED weight! I was running 2 times a day. I would get on the scale and it would go up! ARG. I ate the same low carb way…what is going on? I was overtraining, I went beyond  excessive cardio. My high-intensity exercise  routine pushed the body’s stress response too far, which lead to a cascade of biochemical responses that can caused damage to my health.

Is Cardio Making You Fat?

First, let’s be more specific, MOST people do cardio to lose weight. Some people are more focused on the number on the scale rather than “fat” loss.  The majority of “fat” in our body (over 80%) is collected in one form and stored in body fat cells.  To get rid of it, we can use it as energy which is a process called lipolysis. BUT if you are a “sugar” burner, meaning, you fuel your body with carbs before you exercise, you don’t initiate the human growth hormone to burn fat…. you just burn “sugar.”

Too much cardio stimulates a stress hormone called Cortisol…yes, you probably heard advertisements for weight loss drugs to reduce cortisol, the undesired “belly fat” increasing hormone…Don’t waste your money on these. The easiest and free way to lower cortisol is to sleep! This is why most people gain weight in the summer…not enough sleep. Anyway, cortisol is the hormone that is released when the body is under stress. Stress can be from work, family, not enough sleep, bad eating habits, and excess exercise, such as marathon training, which all stimulate cortisol. All of our hormones go in waves, like the ocean, cortisol is naturally high in the morning, but chronically high levels of cortisol increases your risk for a variety of health issues, such as depression, weight gain, sleep disturbances, and digestive issues. Also, cortisol and testosterone seem to conflict; Aerobic work = more cortisol release = less available testosterone (and you know what that does) while cortisol is elevated.

Exercise triggers the body to release stress hormones, like adrenaline which stimulates the liver to release glucose or cortisol which makes you more resistant to insulin. And strenuous activity, especially competitive sports, triggers increased stress hormones, in which case blood glucose usually increases (at least temporarily). What goes up, must come down. A falling blood sugar is when you feel hunger kick in.
So if you are exercising to just eat more food (I’m not judging, I have done this!), you are making a huge mistake!

Is Cardio Making You Fat?Excess cardio also affects our brain neurotransmitters such as serotonin  GABA, and dopamine which are our feel-good, anti-anxiety brain waves. Craving for carbohydrates and binge eating is associated with low serotonin levels. When you burn these out with stress and intense exercise this leads to feelings of depression, chronic fatigue and sleep disorders. A shortage of these healthy neurotransmitters negatively affect the hypothalamic-pituitary axis, which can cause serious conditions such as hypothyroidism. This is why I ask my clients if their thyroid disorder happened during a stressful event. Stress = excessive adrenal hormone output = adrenal burnout = adrenals steal from thyroid.  Hypothyroidism is known to cause weight gain, depression, constipation and digestive dysfunction along with other undesired problems. Again, stress can be from a loss of a loved one, family stress, work stress, exercise induced stress, not enough sleep and poor eating habits.

Excessively intense exercise can cause a variety of health problems, especially for those dealing with other concurrent stressors such as autoimmune disease, leaky-gut, or adrenal fatigue. On the other hand, short, high-intensity workouts are awesome for stimulating the human growth hormone, which induces fat loss.

Another issue when women complain that they are feeling more tired, losing their hair, and not losing weight with exercise is that they are most likely low in iron. About 90% of women are low in iron due to menstruation, a diet filled with gluten which inhibits iron to be absorbed, and excess cardio. Cardio causes you to also lose iron. Fat loss is all about oxidation… if you lack iron you have a hard time carrying oxygen to the mitochondria of you cell, which is where you burn fat. SO, if you are low in iron, fat burning is hard to accomplish. The problem comes in when we push ourselves too hard and we deplete our body even more of this mineral each time you step onto that treadmill. I have a whole chapter about working out for your menstrual cycle in my book: Secrets to a Healthy Metabolism for more tips on how to burn fat efficiently. 

Is Cardio Making You Fat?

I am still very active, I run in the morning, lift HEAVY weights, practice yoga and walk with my boys after dinner, but I no longer HAVE to run or workout. I do it because I love it.


“Dear Maria and Craig, I wanted to send a big thank you to you for inspiring me back into the kitchen whilst helping my health at the same time! I’ve only been doing your program for a week now and was keto adapted since January. I’m only now seeing real results in my weight loss! The suggestions for supplements have helped my overall well being and the menus are a great way of helping me learn about quantities too. I will definitely write to you again with before and after pictures once I get to where I am happy with my weight and health. Kind Regards, Claudine. (Guetersloh, Germany)”

What are your goals for today? Diet does NOT mean deprivation!

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Maria Emmerich

Maria is a wellness expert who has helped clients follow a Ketogenic lifestyle to heal and lose weight for over 20 years. She has helped thousands of clients get healthy, get off medications and heal their bodies; losing weight is just a bonus. She is the international best selling author of several books including "Keto: The Complete Guide to Success on the Ketogenic Diet.".


  • If you have adrenal fatigue and want to lose fat, would you suggest then to do yoga and weights instead of HIIT or any cardio?

  • Mayra says:

    I loved your post. But, how much cardio is too much?

    • Maria Emmerich says:

      Well, depends on the person and the state of their adrenals. For anyone trying to lose weight I don’t recommend anything like marathons or half marathons. 🙂

  • Valerie says:

    I’ve been adding some exercise into my life, mainly 30 mins of Pilates 4timex a week or so and some long walks. I’ve found the scale to go up a bit 3 lbs or so. My clothes fit the same. Am I gaining lean muscle? As a teen I tended to get bulky when I did a lot of cycling in high school.

    • Maria Emmerich says:

      It could be. Could be a little water retention too. 3 pounds is not much so there can be a lot of things that make a fluctuation of that much. 🙂

  • lisa says:

    Hi Maria, back in my crazy spin days i used to do the chocolate milk after intense workouts. It was the only thing that would help me with muscle recovery and fatigue. i’ve tried many things but unless i ate right after working out, in under 30 mins or less, i would be dead the next day. I don’t live close enough to my gym for this to be possible so i would drink my milk on my way home. Is there some kind of substitute that would work the same? I’m not really sure what it is in milk that does it, possibly a mix of sugar, carb and protein. Is there another drinkable that you would suggest that would be easy to do on the run?

  • Jacci says:

    You refer to excessive cardio as not being ideal later in the day due to increased levels of cortisol….I am by no means fit, and am beginning to add some exercise to my routine, will riding a stationary bike for 30 minutes in the afternoon be detrimental to my weight loss goals? I’m not riding with much resistance, no hills in the program, mostly flat easy riding and my goal is to ride 5 miles in 30 minutes to get started.

  • Laura A. says:

    Hi Maria! I have been on Keri a month now and I have been doing Zumba dice days a week. I workout from 5:30 to 6:30. It’s not hardcore cardio. I would say it’s a ton of leg work with some upper body and then some hurt cardio thrown in the mix. My instructor isn’t all about the dance thing she focuses a ton on resist and using your muscles in her routines. I have noticed a small change and my legs are getting stronger. Is this not the type of exercise I should be doing. If not then what because I love doing it but if it’s not helping me to lose fat then I need to stop. Please let me know what would be a good workout to do and how often. I am the smallest I have ever been in my life but still have some small areas like back fat and cellulite that my body wants to hang on to. I hate it and want to get rid of these trouble areas. In advice would be appreciated. Thanks!

    • Maria Emmerich says:

      I write all about it in Keto Adapted. The chapter on exercise and what I do;)

      Thank you for your support!

  • Laura A. says:

    Sorry for all the typos. Darn autocorret..lol!

  • Sara Whitman says:

    Thank you Maria! I have been struggling with my weight in the last 5 or 6 years, and also found out at that time I am anemic (iron binding saturation was 2, after several iron infusions, and an ablation to stop menstruation it’s improved ) I’m exhausted, but also a Zumba instructor teaching 6 classes a week with no weight loss. I stumbled upon you using My Fitness Pal, bought suggested Quick and Easy Ketogenic Cooking, and I’m now 10 pounds down, and on your blog daily. So glad I found this post on iron, it explains so much. After taking iron for years I can no longer, it tears up my stomach leaving it burning. Any suggestions on other supplements to help without the horrible side effects of the little green pill?

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