I decided I want to lose some fat recently and get a bit healthier. To give myself goals to go for each day I'm using a calorie monitoring app which recommends I have 1750 calories a day. At the moment I pretty much do little to no exercise apart from the occasional day where I go swimming or I am traveling to visit my girlfriend, I do notice that on those days I tend to eat more as I feel more hungry and usually hit around the 1750 mark, varying around 200 calories either way. Although on a usual day I have about 400 calories less averaging around 1200 calories a day.

stats Male age: 21 height: 5,7" starting Aug 18th 185lb now(Sep 1st) 178.5lb (stopped drinking fizzys, eating out less and avoiding comfort foods)

On a day where I might go out for a meal I have sometimes gone over up to about 2000 calories, but this is quite rare. What I wanted to ask is, is the inverse acceptable? i.e. today I have only had 800 calories, although I don't feel hungry or anything, but it does seem very little to me. Could this be bad for my health? If I eat so few calories, will I burn off muscle or get ill easily from lack of nutrients?

What are the negative side affects from having a very low-calorie day once in awhile?

  • Could you be more specific than "bad for your health"? It sounds like you're trying to lose weight--is that what your question is about? Or is it about nutritional downsides of taking in very few calories? Sep 2, 2011 at 0:44
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    I am trying to lose weight, but more so be healthy and get fit. I'll be moving soon and I intend to start running and doing some weight training. I just thought maybe if I eat so little calories I might start burning off muscle or get ill easily from lack of nutrients or something like that. I suppose I should ask... Are there any bad side affects from eating very low calories in a day once in awhile?
    – CurtisJC
    Sep 2, 2011 at 15:10

2 Answers 2


The important aspect is that your average daily intake is about where your recommended calories are.

Another important aspect is where your calories are coming from. If you have very little protein, your body will rob Peter to pay Paul. As your muscles and organs shrink to repair worn out cells, you will eventually run into health implications. This of course reduces your metabolism (fewer overall cells to take care of), which will increase your proportion of fat to muscle.

As long as you keep at least 1g of protein per kilogram of lean body weight, you will avoid that situation (calorie counts for the day aside). This is independent of whether you do high/low carbs, etc.

  • Sounds like I need to be eating a lot more protein! I just looked it up and seems like I am averaging about 1500 calories a day. I suppose when I start exercise I'll need more calories anyway and get the extra protein then possibly achieving the same result. Anywho, thank you for your answer, very informative!
    – CurtisJC
    Sep 2, 2011 at 15:26

Arguments about low-carb vs. low-calorie diets aside, going much below your recommended daily calorie intake will send your body into starvation mode. This is bad and counter productive to your goals.

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