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Not eating vs Eating and Exercising.

I'm confused.

Why is it that if you eat 400 calories a day you feel awful and crash and burn after a few weeks. But if you eat 1000 calories a day and burn off 600 of them in exercise you are fine?

I was thinking that they second method is a lot better because obviously it lets you live a full life. But what is the reason, scientifically, for feeling okay on the latter diet but not on the first? Is your body somehow hiding the calories and not really burning them off??

It just seems like, logically, eating 400 and netting 400 should be the same. But they aren't even close. Now I'm worrying that eating and exercising is somehow less effective than just eating, although I know it can't really be the case!



  • Leanne1795
    No, it is simply that by eating and exercising you are fueling your body for the exercise. By not eating you are just starving your muscles etc. It's like if you drove your car without fuel. It would stop! Fuel it a bit and it can keep on going. :)
  • SlimSadieG
    SlimSadieG Posts: 323 Member
    You shouldn't be consuming or netting 400 calories a day ever!!
  • Sezmo83
    Sezmo83 Posts: 331 Member
    You shouldn't be consuming or netting 400 calories a day ever!!
  • Kalrez
    Kalrez Posts: 655 Member
    Long-term, there isn't much of a difference except for the fact that you're strengthening your muscles by exercising. In the end, though, you still only consume 400 calories. It'll catch up with you.
  • cownancy
    If you are eating 1000 calories and working off 600, you won't "be fine" for very long. You need at LEAST 1000 calories net per day, preferably 1200, unless you are under a doctor's supervision and taking supplements, etc.
  • hamncheese67
    hamncheese67 Posts: 1,715 Member
    Because you and your body depends on getting the proper amount of nutrients to feel good and function. If you a 1000 calories worth of fruits, vegetables, and meats, you'll feel and function better than eating 1000 calories worth of twinkies and ding dongs. Exercise stimulates your muscles, improves blood flow, etc. and all that helps you feel and function better too.
  • jagoochie
    jagoochie Posts: 218 Member
    if you dont eat enough to fuel your muscles then your body uses up all your glucagen supplies and turns to burning your lean muscle, and your brain doesnt getthe sugars it needs quickly enough, so you will feel pants
    if you eat then your body can use that energy for its systems and this then enables it to mobilise and matbolise the fat as it is keeping the reserves its needs for your brain and functions
    (its a bit more in depth than this, but that is the jist)
  • delightful
    i try to eat all of my goal calories for the week, i have over my journey done both, sticking to just my food intake and combining the 2 (food and exercise) you do feel great doing both, and i think that is the key, but when i have been really busy i have lost and maintained weight with just watching my food intake alone.
    don't be worried, just focus on eating healthy and exercising because you enjoy it
    and p.s the 400 cal thing leads to burnouts and binging! (been there)
  • MrsSWW
    MrsSWW Posts: 1,585 Member
    You shouldn't be consuming or netting 400 calories a day ever!!

  • burns65
    burns65 Posts: 1 Member
    My goal intake is 1200 calories. I always have this many. If I exercise then I can eat more. I usually exercise every day, some days it might be only a quick walk giving 200 cal or so. Other days a full on gym session can give 600 calories. I have been doing this since May and have lost 25lbs. Roughly 1-2lbs a week. I rarely feel hungry or deprived and don't feel tired. Netting 400 calories really is not a healthy option. Loosing weight too quickly is not sustainable. Sorry if this sounds 'preachy' - but you are putting your well being at risk by having such a drastic approach. Good luck!
  • rachel1496
    A 1000 calorie diet would give you a better chance of getting all of the nutrients you need so even though you end up with the same net calories you consumed more protein, fibre, calcium etc; A 400 calorie diet would make it very difficult to get enough of anything.
  • Joh4nn4
    I think i have a good answer to this. ( I hope) If you are just eating 400 calories a day, your´re not getting all the vitamins and nutrition your body needs to be alert. And you´ll get tired. But say that you eat 1000 calories and burn of 600 by exercising, your body has already taken up all the important nutrition, vitamins etc in the food. And you feel more alert! Although your net intake of calories is 400. And i apologize for the crappy english! Have a nice day,

  • jellybaby84
    jellybaby84 Posts: 583 Member
    Thanks, that does make some sense. I will try and stop freaking out that I need to be eating a starvation diet then!

    And the 400 thing wasn't the relevant question really. I could have inserted any number (eg is eating 1000 the same as netting 1000). The reason I quoted my 400 was that, while I personally believe I am fine to net 400, I know there is absolutely no way I will be fine if I only eat 400. Whereas if I'd said 1000 the question wouldn't arise because I would feel fine both eating 1000 AND netting 1000. I don't always net 400 at all, it can be quite a bit more.