Does Running Make You Fat? – Debunked

Warning…the first seven paragraphs are a preamble. If you just want the tips, feel free to skip to the “Meat and Potatoes” section.

Several months ago my wife told me I need to read a blog post one of her friends shared on Facebook. Her friend shared the post with an attached comment of “This really makes sense”. The post was an amateur post by a personal trainer who makes the claim that running makes you fat. An impressively long list of over 80 references followed the post, making this claim look legitimate on the surface.

I read the post. The author did a great job selling their theory. They did such a great job that I began to doubt my knowledge on this topic…and yes, I am very well trained, read, and researched on this stuff. According to the post, steady effort exercising, such as running and cycling elicit “self preservation”, a state where the body slows metabolism, thyroid function, and fat utilization in order to “save itself” from dwindling down to nothing. Now, I am trained in this stuff, and I knew this to be largely untrue except in specific circumstances, however this list of references was really impressive. In addition, the titles of most of the references supported this conclusion. Could I really have been led so far astray?

So, I pulled out the credit card and dropped a bunch of money on the full reports for many of the referenced studies. For the next week I spent my lunch breaks reading the complete studies. The good news following my review was that I no longer doubted my expertise. The bad news was that this post was irresponsibly written, poorly researched, inaccurate, and self-serving. The majority of the studies from the list of references, when read in their entirety, had much different findings than the titles would lead one to believe.

The post was spreading like wildfire, influencing hundreds of thousands of people into believing that running, triathlon, and cycling are not good for them. What reading the full studies led to is a conclusion I was already familiar with, which is that under certain circumstances the body will go into a “self preservation” mode. The author took this particular consequence due to certain circumstances, and generalized it to everyone. I’m giving the author the benefit of the doubt and chalking it up to inexperience.

Initially I blew it off. However, in the last several months I have been seeing more and more articles making the claim that running will “make you fat”. The posts seem to be getting more dogmatic as well…this is the way it is and we are right! I even read one rather strong article by an exercise physiologist turned testosterone supplemented beach body trainer ranting about Ironman athletes and marathoners idiotically setting themselves up for getting fat with their training. For those that have competed in, or at least watched, an Ironman, it has the appearance of a giant meeting of the fittest looking people on earth. As some of my friends say (male and female), watching an Ironman is eye candy. In a funny twist, this particular gentleman has a picture of himself on his website without a shirt on…and interestingly, he would be the “fat guy” toeing the line of an Ironman.

Well, after reading too many of these articles I can’t stand it anymore, I need to debunk the claim.

Meat and Potatoes…because that’s what us endurance athlete fatties love most, right? 🙂

Does running make you fat? No. Can it? Given the right set of circumstances, it can lead to slowed metabolism, hypothyroidism, and fat preservation. Are these circumstances avoidable? Absolutely. Should you continue reading this so that you know how to avoid these circumstances? Yes. Can running lead to fat loss? MOST DEFINITELY! Are endurance sports a good way to “get skinny”? Yep.

The truth is that our body tolerates steady state exercise extremely well. In fact, many experts on exercise physiology believe that our physiology is made for steady state exercises. My opinion is that we are an incredibly adaptable species that can thrive doing both burst activities and steady state activities. Just look at the incredible adaptability in football players, who are able to explode out of a crouch and push with enormous forces, compared to Ironman athletes who are running sub-6 minute miles after swimming hard for nearly an hour and biking hard for almost 5 hours. Both are very different, yet we are achieving mind-blowing feats in both. I don’t think it is fair to say we are meant for one type of activity.

When the body is given the fuel it needs and limits are not exceeded too quickly, running is great for your health. It is also convenient. You don’t need a gym or fancy equipment. You just lace up a pair of shoes and go. Mentally, running has incredible benefits. Research links running to reduced rates of depression, mental illness, suicide, and greater happiness.

Physiologically, we also tolerate running very well. Adaptations in hormones, red blood cell turnover, metabolism, and fat burning are clear indicators that our bodies are meant to do endurance activities. If we weren’t, some of the adaptations, such as the transition between carbs and fats as fuels, just wouldn’t occur.

As I mentioned, circumstances do exist that may lead to a state of “self preservation”, which is characterized by slowed metabolism, fat preservation, decreased thyroid function, and more. The circumstances are largely related to dieting or nutrient deprivation, such as low fat diets while training. Here are some tips to ensure you avoid sending your body into “self preservation”:

1. Do not restrict calories when initiating your training. The start of endurance training is NOT the time to start a new diet. If weight loss is a goal, ramp up training for at least 4-6 weeks and then start cutting calories in small quantities, if you are not dropping weight already, until your calorie output slightly exceeds your calorie input. During training, do not restrict calories more than 200 less per day than what you are burning, and do not sustain this deficiency for more than a week or so at a time without 2-3 even calorie days (in equals out).

2. Eat fat! The 90’s brought about a fear of dietary fat. I remember a good friend of mine in high school once saying at the end of the day, “Yes! I only ate 2 grams of fat today!”. Fats are absolutely essential for hormone production, and the absorption of many essential nutrients, such as Vitamin D. If you are not eating fats during training, your body will do all it can preserve body and dietary fats. In addition, your training and racing will suffer because your body will not go into a fat burning state as quickly…if at all.

3. Make your calories count. Before you eat or drink anything, ask yourself “What is this doing for me?” If the answer is nothing, don’t eat it. Of course, there are definitely times for exceptions to this rule…I’m not a complete stick in the mud. But, in your daily diet, every bit of food and drink you eat should provide your body with something it needs. Eat your veges. Eat your fruits. Eat adequate amounts of fats and proteins.

4. Do NOT crash diet…ever.