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Three reasons why you can't out exercise a bad diet

You may have heard it said before but it's true, you can't out exercise a bad diet. It's something I learnt myself when I lost weight. I've always been an active person and I figured that whenever I ate out a lot or had a string of social events to go to I'd just do an extra session or two at the gym. It's a nice idea but unfortunately it doesn't work like that.

Don't get me wrong, being active is important. If you are looking to lose weight then increasing your activity levels will certainly help your efforts but it's a myth to suggest it can undo bad eating. Here are the only three reason you need to work on your diet as well as your activity levels:

1) You're not a professional athlete

Which means it's unlikely that the maths will add up.

  • If I have a slice of pizza I will have consumed approximately 285 calories.
  • To burn that off I have to run for about 30 minutes (and I run regularly so it's at a reasonable pace).
  • The problem is I can eat that slice of pizza in 2 minutes. If I have a second slice I'd need to run for 1 hour to burn them off.
  • On top of this I'd need to do more exercise for every extra cake, crisps, glass of wine etc.

Any of these foods are fine in isolation but if you add up all the excess calories you can consume in a day or week they take minutes to consume but hours to burn off. I don't know about you but I don't have enough time in a week to make up for all that. It's much easier not to consume the additional calories in the first place


2) Most people are terrible at estimating their calorie intake

Studies show that people typically underestimate the calories they consume by 30%. One problem is that people don't always feel comfortable acknowledging extra calories they consume. The other problem is that is it genuinely difficult to remember everything you have eaten or drank. You might forget about the coffee with syrup you picked up on the way to work, the sweets you ate without thinking in the car or how many beers you had last night. All of this added to the fact that most people tend to underestimate their portion size means it's actually very hard to accurately know how many calories you consume each day. Particularly if, like most people, you eat different foods each day. 

What about the other way round? Do we accurately estimate how many calories we burn?

No. Studies also show that while we underestimate the calories we consume we tend to over estimate the calories we burn. Modern apps and fitness devices can help but they are only as good as the person entering the data and typically, when given a list of food types/quantities most people enter the lower numbers. They can also be inaccurate, even when you enter the correct data. My S Health app seems to think my 10K run burnt off as many calories as my partners marathon. I wish it was true but I doubt it.

3) It's quality not just quantity

Even if you do accurately track your calories it's the quality of food you eat that makes a huge difference. You may be carefully watching your calorie intake but if you're getting those calories from unhealthy foods it wont help in the long run. How much fat are you consuming? How much carbohydrate? What about salt or sugar? Too much of any of these can all have a negative impact on your body, even if your overall calorie intake is balanced. 

Not only can unhealthy foods cause problems for your body but not meeting your nutritional needs with the right foods is disastrous for weight loss. Someone once said to me:

You can eat 1000 calories a day of anything and lose weight. You could eat 1000 calories of only chocolate everyday and you’d still lose weight. However, you’d be very hungry and eventually you’d be malnourished”

This really hit home for me. Exercise might burn off additional calories but if I don't eat the things give me energy and meet my nutritional needs I am going feel terrible. The problem with that is it might result in me feeling hungry which will make me hangry, tired and ill. All of which is going to weaken my resolve and give me less inclination to diet and do more exercise. If I feel rubbish the chances of me doing that extra exercise are extremely slim, compounding the problem.


So should I not bother exercising?

Not at all. As I say, exercise is important. It has many benefits besides helping you lose weight. It's great for improved strength, stamina and it's good for your heart. It can help boost your immune system, increase confidence and help you widen your social circle. However it can't undo the impact of a poor diet and it's unlikely to chalk off those extra calories you consume.

What are your experiences?

Do you feel that you can accurately estimate your calorie intake?

What role does exercise play in helping you lose or maintain your weight?

Do you use any apps or fitness devices? Do they help?

Share your ideas and comments on the Slim Thinking Facebook page. (Click join and you'll be added if you haven't already).


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