Running for Weight Loss

How to consistently lose weight with running.

1. A Hard Truth

First of all, a hard truth: if you are overweight it means you are eating too much. Now, mind my words. I didn’t say you are eating a lot, I simply said you are eating too much.

Let’s start from the beginning.

Food is our source of energy; it is the fuel that allows us to perform every task: from basic ones such as breathing, pumping the blood around the body and walking around to complex ones such as carrying the TV up the stairs or running when you’re late for the bus.

Our bodies are efficient machines. We come from a time when food was scarce and reducing waste was key to survival. Fat is the way your body stores extra energy. When you eat more than what your body needs, your brain doesn’t go “oh well, this is extra, I don’t need it – let’s get rid of it”. What your brain thinks is “Fantastic! Extra energy! Let me store this in case tomorrow you won’t be able to hunt a bison down so we can use this energy instead”.

Your body then proceeds to process that extra food and transform it into fat, which then gets stored under your skin a bit all around your body: your gut, (man) boobs, bum, legs and face.

You see, your brain doesn’t see fat as a bad thing. It sees it as a fantastic way to ensure survival in case you won’t be able to find food in the future.

2. The Good News

The good news is: the reverse process also applies and it’s also very efficient: if you don’t introduce enough fuel (energy/food), your body will promptly go and take it from its fat reserves.


The Caloric Deficit

We keep talking about energy and fuel because it’s an easy way to picture it. In science, this has a name which is CALORIE. A calorie is a unit of measure of energy. So you can replace everything you read as “fuel” in the paragraphs above with “calorie” and it will still be exact.

And why is this important? Because we can calculate it and plan our weight loss around it !

A Caloric Deficit represents the amount of calories that your body doesn’t get through food and has to go and find in its fat storage… (almost) literally burning it.

It’s actually very easy: eat less calories than the calories you burn and you will shed fat away.

3. Your Basal Metabolic Rate

The Basal Metabolic Rate (BMR) is simply the amount energy (calories) you burn each day at rest. Even when you think you aren’t doing anything, you are using energy to breathe, move around, keep your muscles active.

The BMR varies by individual and depends on a lot of factors such as gender, height, weight, body composition (fat vs. muscle)…

There are many formulas to calculate your BMR and you can find a good calculator here:

Let’s use me as an example. I am a 34 year old male, 6.2” for 185 lbs weight. My BMR is 1927 calories per day.

That means that if I do nothing all day and I eat 1927 calories, I will neither gain or lose weight. But we do indeed do something every day. Just walking around and moving will put more more or less at 2,200 calories (use the link above to calculate your values!).

So if I want to lose weight, I have two choices:

  1.  Eat less THAN 2,200 calories
  2.  Be more active and consume MORE than 2,200 calories

4. How running HELPS you lose weight

Running is a calorie-consuming activity. When you run you contract and release many muscles – in the legs, feet, arms… your heart rate goes up to keep feeding oxygen and nutrients (through the blood) to the muscles.

Do you remember the caloric deficit? By running you increase the calories you burn during the day. This is a ballpark figure, but it’s estimated that running 1 mile burns 150 calories (it’s a very average value and depends on many factors including your weight, running efficiency…).

So if I run 3 miles a day I will burn an extra 450 calories each day. It means if I keep eating the same I will lose weight!

How much weight? It is calculated that 1 pound of fat equals 3,500 calories. 1,800 calories a week (running 3 miles a day 4 days a week) means half a pound of fat per week. This if you eat to your daily caloric need. Chances are, if you are overweight, you eat more than that already.

Is it less than you were hoping? Don’t worry, you can lose more.


Slow and Steady wins the (weight loss) race.

Running is an amazing way to lose weight, but you need to understand that you need to build it up. When you start running you probably won’t even be able to run those 3 miles. Most beginners’ running programs will have you run-walk 3 times a week for a month before you can run 3 miles.

STICK TO IT! After all running is an endurance sport and as such, patience is what brings the best rewards. Don’t rush distances/speeds you are not ready for yet. They will come and it will all make it better very soon.


5. Why running WILL make you lose weight

As we said before, your running condition will improve with time and three things will happen:

  1. You will be able to run further
  2. In just a couple of months you will be able to run 8 miles in one session. Run 3 times a week for 8 miles each session and your weekly calorie expenditure will be 3,600 calories or a full pound of fat!

  3. You will be able to run faster
  4. Running faster will make you burn MORE calories per each mile.

  5. You will put on muscle

Remember your BMR (Basal Metabolic Rate) ? It’s higher when you have more muscles. That is because muscles are alive and need constant feeding just to be maintained, while fat just sits there.
Running will slowly but surely build muscles – especially in your legs. These muscles will consume extra calories even when you are not running, just because they are there !

To summarize: running is very hard at the beginning and you might not see results for a while (in terms of weight loss, but of course things like your cardio efficiency will be immediately and noticeably better). But keep running and in just a few months you will be a fat burning machine !


6. How to MAKE SURE you will lose weight (or, “mistakes to avoid”)

In the beginning the amounts of calories you will be burning is going to be low. And you will be very tired, because running is an effort that you are not used to.

You will feel like you spent more energy than you actually did.

Remember. One 3-mile run will burn 450 calories (approximation!). After the run you think “I need to re-hydrate, let me have a Gatorade”. A bottle of Gatorade has 300 calories. Does it make sense to run 3 miles to only reap the benefit of 1 of them? Energy drinks have a place, but when you run less than 1 or 2 hours, stick with water.

Also, many people think “Well, I ran this morning, I can treat myself to a candy bar!”. Do you know how many calories in a standard bar of Snickers, Mars or Lion? Almost 300. Two of your three miles are gone.

If you want to lose weight while running, don’t add calories to your diet. Not at the beginning.

What to eat ?

I am not a cook, but in our household we started cooking some of the recipes from the Metabolic Cookbook by Karine Losier. They’re easy to cook, tasty and with a decently low amount of calories – we don’t see it as a diet, just food to cook for the family. Try it out!


Last word of advice: don’t take shortcuts.

a) Running is a taxating sport for your body. If you aren’t patient and increase mileage/speed too fast you can get injured. This means pain, no running and no weight loss.

b) Decreasing your caloric intake is a good step, but don’t take it too far. You can easily and healthily burn 2-3 pounds of fat a week. But if you keep underfeeding your body, your brain will start breaking down the muscles instead of the fat (the logic is “we don’t have enough energy to survive! Let’s cut down those high-maintenance muscle fibers!”).


(this article first appeared on

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