Why Burning More Energy Than You Consume Won’t Help You Lose Fat – And Could Make You Gain It!

Read time: 90 seconds

You may like to sit down for this one – if you’re a cardio queen or gym bunny from way back then it could come as a shock. You see, I’m about to explain to you why the weight loss rule that you need to expend more energy than you consume is – for the most part – absolutely, irrevocably WRONG.

That’s right.

Whoever said that ‘energy in vs energy out’ is the way to go if fat loss is your goal, is selling you a lie. Unwittingly or not. According to the energy in vs energy out rule, losing weight is a cinch as long as you simply eat less calories than what you burn. As a (very) general rule, women wanting to lose fat are advised to consume something like 1200-15oo calories, and men are often advised to take in between 1600 and 2000. If you’re a facts and figures kind of person then (in theory) this makes slimming down real easy. After all, an hour of really hard-workin’ cardio on the elliptical will often net you an 800 calorie deficit. Logically, therefore, doing 2 hours of cardio, or perhaps an appropriately calculated mixture of group exercise, cardio, and the occasional weights session will have you looking the bomb in no time. Add in some calories burnt for daily activity and for staying alive (digestion, breathing etc actually burns up a fair few as discussed in this post about burning fat while you sleep), and you can’t help but succeed.

Which makes it all the more strange then, that most people following this plan are still waiting for it to ‘kick in’. I mean, surely not ALL of them are lying about how much they’ve eaten?


While it would be nice to think that we’re smarter than our bodies or that math rules all (if I eat 1000 calories and burn 1500 I MUST lose weight), if you are serious about dropping some pounds, you’re going to have to face facts. Your body is smarter than you are and, what’s more, will actually fight your efforts by programming you to store MORE FAT if you take this energy in vs energy out rule too far.

It’s called the survival rule, and it goes like this:

  • You cut back on your calories, especially those that come from fat
  • Your body (which has no idea you live in the 21st century) assumes that food must be scarce, or that you’re on the run from something dangerous.
  • It goes into cortisol (stress hormone) overdrive IMMEDIATE FAT STORING ACTIVITY. In order to make sure you don’t starve and die, your hormonal system switches begins using stored muscle for energy (because stored fat will keep you alive longer), while at the same time releasing more cortisol to help you to store fat faster.
  • If you’re female, this effect is accelerated. After all – what if you became pregnant?
  • You decide to up your exercise quota. An extra cardio session each week – or each day! Talk about the worst thing you could do …
  • As far as your body is concerned, not only is food scarce, but you’re now running or fighting for your life! Why else would you be doing so much cardio?
  • In response, there is a slowing down of your digestive system, a lowering of your metabolic rate (energy conservation), and yet more fat storage. After all – who knows when you might get a chance to eat again?
  • After a few months (or, God forbid, a few years) of this sort of lifestyle you’re tearing your hair out and just about ready to give up on ever getting in shape as you wonder what bad genetic program means you just don’t lose weight despite ‘doing everything right’.

The solution is simple

I’m not saying calories never count. Of course they do. But trying to trim off caloric intake in response to increasing caloric expenditure is a sure-fire recipe for disaster for all the reasons listed above. If you want to look and feel your best you need to eat enough (real, full fat, protein and green-veg orientated) food to sustain metabolic activity, and focus on quality exercise that builds your metabolic rate. This means train hard – but if you want to actually train your butt off, then do so with weight lifting, and perhaps a very LITTLE amount of high-intensity interval training. Treat your body the way it was designed to be treated for optimal health and stop trying to run it into the ground. Trust me on this – you will NEVER beat your own physiology, and sometimes less really does equal more.

Do you have any personal experience on losing body fat once you gave up cardio? I can’t tell you how often I receive a shocked email from a reader or client saying that (usually after being forced, as they’re too scared to otherwise) after giving up cardio they’ve rapidly lost several kilos. Perhaps you always lose weight when on holidays despite doing less? Please comment below!


17 responses to “Why Burning More Energy Than You Consume Won’t Help You Lose Fat – And Could Make You Gain It!”

  1. Ginger says:

    This is so great and I couldn’t agree more!!! Not only all of the above that you mentioned, but once the “starving” yourself novelty starts to wear off, you’ll eat more than if you just ate sensibly from the beginnning.
    Thanks! Great article!

  2. CHANELLE says:

    Great post! This is info. that more people need to understand!

  3. Guy Lawrence says:

    Hi Kat

    I stumbled upon your blog a few weeks ago, and have enjoyed reading what you have to say 🙂

    And i couldn’t agree more with your latest post. For anyone who’s interested in this area, i’d recommend the book ‘Good calories, bad calories’ by Gary Taubes, if you haven’t already read it. Extremely well put together and researched. A great read!

  4. Talitha Natt says:

    I did wonder a few years ago why I lost weight post completing a half marathon ?!!! The answer is evidently clear now!! And needless to say, I am no longer pounding the pavement!

  5. Guy Lawrence says:

    Great post Kat… There’s a great book called “good calories, bad calories’ by Gary Taubes. Give it a read if you haven’t, highly recommend it. Extremely well put together. 🙂

    • Kat says:

      Hi Guy. I LOVE that book -it’s been in my bookshelf for years. I think I initially heard of it through Dr Eades. Good reminder for me to dust it off again. Have you read ‘Living the Low Carb Life’ by Jonny Bowden? That’s another must.

  6. Kat says:

    Hi Kat,

    Thanks for the seminar @BYJ last week. It was very informative & I’m now eating some protein before the 5:45am classes & flying through!

    In regards to this post I was very guilty of this. I was a total gym nut doing up to 12 group fitness classes a week, mainly all the cardio ones. When I had my appraisal with a trainer with all the measuring & weighting etc. I was shocked my body type came out as ‘not excercised’ with 28% body fat. I was a size ten and didn’t look out of shape. The trainer put me on a weights program & told me to cut out the cardio classes. I was aloud to warm up on the rower for 4 minutes!

    I’ve not had another appraisal yet to compare but I quit the gym completely since discovering Bikram in July. It’s all I do now with some Body Balance and I can see the difference. I’ve lost weight around my mid section, lost a dress size & my own scales are registering a 20% body fat reading.

    Thanks, Kat.

    • Kat says:

      Hi Kat,

      That’s SO good to hear how well Bikram has worked for you. I just love that yoga so much; I don’t think for a second that I’ll ever choose to be without it. Even when I’m traveling I go out of my way to find classes; it’s almost as important to me as finding good food.

      I do think it’s important to include some weight training though. Not just to increase lean muscle tissue and speed up fat loss but also for health factors such as bone density. Yoga alone just won’t work in the same way. It sounds like that trainer was on the right track 🙂

      Keep up the good work with your nutrition and let me know if I can be of help – and thanks for being at the seminar!


  7. Guy Lawrence says:

    … No haven’t read that book.. as yet anyway 🙂 I’ll be sure to check it out… it’s always great to here peoples thoughts on the topic.

  8. Carla says:

    I go back and forth on this issue for me. Lately I increased my cardio – HIIT (still doing 30-45 minutes of weights on top of that) and it has done nothing for me. I do all this four days a week or every other day. I guess I fear not doing cardio because I like to stay fit because I already have a lot of endurance.

    Should I cut the cardio do one or two days a week? I use the skinning bikes for about 15-40 minutes at a time.

    • Kat says:

      HI Carla,
      The more I learn about cardio, the more I believe in the need to REDUCE it for most people. I’d recommend only 1-2 interval sessions per week, with the rest of your regime being weights (3-4) and maybe some yoga.

  9. Janet Darbey says:

    Hi, I am new to this great site. This was a very interesting article to me. I competed in the 1980’s in the early female bodybuilding shows in the UK. At that time I was extemely lean and low body fat and I did no separate cardio whatsoever, just three hardcore weights workouts a week and one or two evenings of kickboxing. I gave it up after four years of competing only to return to it three years ago.
    I am now competing again in physique contests at the age of 55. I have lost 23kg in weight by eating healthily six times a day and doing heavy weight /low reps training for an hour three or four times a week. I have now started back at kickboxing but go once a week. If I do any cardio its just a warm up on the incline treadmill or cross trainer for a few minutes before the weights. I also do a pilates class to stretch out.I have never felt fitter in my life!

  10. TN says:

    This may just be what I needed to read this whole time…

    I am in my second week of healthy eating and regular exercise – I’ve been eating around 1200 calories a day because I’ve read that this is the minimum recommended intake for women.

    So I’ve noticed that I feel better etc but I’m not expecting any drastic changes quickly – and I have been exercising a considerable amount more than I ever have, plus probably eating considerably less calories than I always have! Does this mean if I stop this suddenly and tone everything down a little, I’ll lose weight? And will I keep losing weight if I stayed that way?

    Also now that I think of it, last year I had a short period where I exercised and ate as healthy as I could – and as soon as I stopped doing so, I lost weight! Thinking that not eating much and eating junk when I wanted to was the trick, I didn’t eat much… so my weight fluctuated, I seriously could SEE a difference in my thighs within a couple of nights sometimes! Then not-too-frequent but often bingeing for months has lead me here, trying to lose weight again!