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Fasting For Weight Loss – Calories Still Matter

by Dave on March 5, 2010

Fasting For Weight Loss –  Why Calories Still Matter

Fasting For Weight Loss

Fasting For Weight Loss

One of the pleasures I get from this blog is the personal messages I get from  people who are also becoming retired dieters, even some of my friends who long thought I was nuts to be using intermittent fasting to lose weight have been converted and are now quietly incorporating 24 hour fasts into their weekly schedules.

One thing that keeps coming up is  ” Dave I fasted twice this week but I didn’t lose any weight ”

Even when using fasting for weight loss, you need to understand the amount of calories you consume is important. Taking a 24 hour break from eating is a great way to burn body fat during that 24 hour period, but if  you then break the fast and consume more calories than your body needs, you will not lose weight.

So let me make it clear….

When Fasting For Weight Loss  Calories In V Calories Out is what matters

To lose weight you need to consume LESS calories than your body needs. Intermittent fasting is just a tool to help you do that, but unless you are eating less than your daily requirement, you will not lose body fat. Yes you will burn fat during the time you are fasting,  but if you then eat above your required calories, you will just replace the fat you burned.

As a retired dieter I don’t refuse the foods I love, I just make sure I eat less calories.

One problem for most people is they don’t know how many calories a day they need , we then also under estimate the amount of calories we consume.

Let me give you an example based on my current measurements.

Fasting For Weight Loss – Working Out Your Calorie Needs

Using a simple Resting Metabolic Rate ( RMR ) calculator , you can work out your daily RMR/BMR . Go there and enter your details to find your own BMR number …  please ignore any weight loss fad diet ads that may display.

In my case, as  a 45 46 year old male with a current weight of 174 lbs  and a height of 5 ft 10 inches, my BMR/RMR is about  1730 calories a day. That number is based on me doing nothing and staying in bed all day. As my work is Internet based, and my office is at home, in my case this figure would not be far off. Only adding exercise to my daily routine will increase the amount of daily calories I need. Sitting in a chair at a computer screen all day does not burn too many calories.  So in my case 1700 calories a day is what I try and work with.

As I work from home, I do take a daily break from the laptop and take a walk.  If we use the equation of 1 calorie per  kilo of body weight  per kilometer distance travelled, this would burn extra calories as follows.

174lbs = approx 79 kilos .   so walking 1 kilometer would mean I burn around 79 calories. If I do a 5 mile walk that is 8 kilometers  so that is 632 calories.

As I mentioned in this post about my six pack abs mission I look at my calories over 7 days, not daily. I eat more on a weekend, and reduce the calories on the weekdays when I am working.  12000 calories a week is what I try to work with. The intermittent fasting just helps make this easier to do.

Again we come back to the basic process that weight loss is not complicated. If you want to lose fat, then you need to be in a calorie deficit. This can only happen by eating less calories than you need, or by increasing the number of calories you burn off with exercise.  Intermittent fasting helps you eat less.  Even something as basic as walking gets you burning more calories. Use bodyweight exercises to maintain muscle, and you are on the right track. No gyms, no fancy diet plans, just a simple, no fuss  way to lose weight.

In A word ?  Eat Less Move More Eat Stop Eat and Anything Goes Diet are my suggested ways to reduce calories for weight loss

Any questions about fasting for weight loss ? please leave a  reply in the comments

Want To Know More About Why I Am A Retired Dieter ? Want To Know How Lose Weight Using Intermittent Fasting ? Then Enter Your Email Below And Get My Story

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  • Lisa Meyer

    Hi Dave,
    Thanks for sharing so much. I’ve been doing IF since 1/26/2010 and have lost 11 lbs because I think I am eating less calories per day. When you say your BMR is about 1700 calories/day does this mean that your target is just to eat 1700 calories per day. How much less do you eat per day in order to continue to lose weight. Thank you! Lisa

    • Dave

      Hey Lisa,

      first congratulations on losing 11lbs, nice going.

      If I ate 1700 calories a day and just went from bed to laptop, and laptop to bed, then I would more or less stay the same weight. Of course most of us do a least something, but if I was not to do any exercise at all, then if I currently wanted to lose body fat just from my diet I would need to be at around 1200 calories a day, or 8,400 per week to lose 1lb of fat. Again a big mistake people make is thinking that eating 500 calories a day less will lose 1lb of fat, but that only works if it is 500 per day below your daily requirement.

      I work on 12000 calories a week , but include a daily walk and of course my bodyweight exercises 2 or 3 times per week.

      Hope that helps


  • ryan

    outstanding post. i watched a documentary where a tv crew followed an overweight woman around and monitored her caloric intake via various methods. they had her track her calories as well (the premise of the show was debunking the “slow metabolism” excuse that she was using). the result? she was underestimating her calories by about 60%. this person was not delusional, i think many of us are guilty of this- the show was a real eye opener for me. it is crucial to keep an eye on the calories per week, or 3,5 day periods, no matter what the daily activity level is.

    walking is a great idea as a daily breakaway from the computer. i attempt to get a good one in every day i don’t make it to the gym. however, i think your calorie burn figures are too high. my numbers show that you would burn 300-400 cals on a 5 mile walk, assuming you are going about 3mph.

    anyway, congrats on the success. the blog is very inspirational- please keep updating us.

    • Dave

      Thanks for the compliment Ryan,

      I agree with you, The person in the tv show just highlights what we all do, and I am no different. I just find tracking my calories is a little easier if I didn’t eat anything !

      You may be correct on the walking, though got the numbers from a study somewhere, but can’t find it now. Saying that, I did find Brad Pilon using the same numbers in this video here .
      I walk at fast past, as it takes me on average 1 hour five minutes, but from what i understand the calories burned does not change, if I ran the same distance I burn the same calories, I just do it quicker. I agree though, walking is a great way to unwind and clear the head.

  • Margery


    What a timely post! I have lost 13.3 lbs since the end of Dec to now but stopped losing because I have not been minding how much I am eating. So now I am keeping a food journal to track what I am eating during my meal. My caloric intake is way too much and it explains why I have not continued. Great post! Thanks for the information.

  • Jonathan

    Hey Dave,

    So you’re saying I really need to cut out that bowl of ice cream most nights? ARGH!!! You’re killing me man!

    Just kidding.

    But seriously, I think I’ll start losing weight faster by cutting back on calories as you’re talking about – it’s really just basic math I guess.

    Still, feeling pretty happy about having lost nearly 10 lbs since Mexico one month ago!

    • Dave

      Hi Jonathan,

      LOL you know I would be the last person to say you need to cut the ice cream. That is like telling me to stop drinking beer, each to their own as they say.

      If you want the ice cream most nights, then have it, but just be aware of how many calories it is. If you don’t mind missing it for an evening then it’s all good, but you don’t want to feel that you are missing out. That 10lbs shows you can lose weight and still have the ice cream ;)

  • Lisa Meyer

    Thanks Dave for your response. I understand now that I should try reducing about 500 calories from my BMR. I do brisk walking 45 minutes per day. With this type of exercise I understand I burn about 329 calories. Do I add this to my BMR and then reduce by 500 calories or do I just use my BMR number. Thanks again for your story. You are an inspiration!!

    • Dave

      What many make the mistake of doing, and I have done it in the past is to think ” oh I burned 400 calories with exercise today, I have 400 more cals to eat ! or in my case 2 pints of beer to drink !. If I am trying to lose, that is not the way to look at it.

      Again I think stepping on the scales with a realistic goal in mind stops that feeling of depression if the scales don’t seem to have moved. If over say 4 weeks there is no change, ok, then in most cases we know the problem is we are still eating too many calories, but if month on month you are trending down, my advice is be happy !.

      When you are losing actual body fat and not just fluid you will notice the difference in your clothes and in the mirror, not always with the scale, this is even more the case for Women than for us Men.. we do get off lightly with mother nature ;)

      I will qualify that by saying that, if I am honest, when the scales don’t move I still don’t like it, but I have done this long enough now that I know to look at the bigger picture, not what happens from one week to the next. Our lives are varied, perhaps you had a meal out the night before a weigh in, so the scales show a 3lb gain, what you need to remember is to gain 3lbs of fat, you would have had to consume around 10,500 extra calories above your BMR, so that 3lbs the scales are showing is going to be mainly water. Eat less for a day or two and you will soon see things come back in line. Trust me I know from over 14 months of living my life as a retired dieter there is just no way that in the last 14 months I have not gone to parties, visited restaurants or been out and from time to time, drank way more than I should. I still lost the weight, and I have continued to keep it off, I didn’t lock myself away for the last year or so, I continued to live my life, but with a couple of simple changes, and those are an understanding of how many calories I need, and then using Intermittent fasting as the tool to manage them.

      So to summarise, my advice at the moment would be to use your weekly BMR calories as your calorie limit, and based on your daily activity see if your weight is dropping. If you feel comfortable reducing from you BMR, again this is up to you. anything below that number and you will lose body fat.

      Keep me updated


  • Lisa Meyer

    Thanks again Dave. It’s good advice to look at the weekly calories as opposed to the daily calories. This allows me the freedom to eat a little more on the weekends and a little less during the week. I’m just wondering is there such a thing as not eating enough calories. Everyone tells me that I will go into starvation mode and will lower my BMR. Is this something I need to worry about.
    Thanks for your help.

    • Dave

      ” starvation mode ” is just a term used by the diet and fitness marketers, usually by the ” eat six meals a day or your metabolism slows down ” crowd. There is no such scientific term as starvation mode, and the people who tell you about it, are just repeating the same rubbish they have read somewhere. Ask them to point you to the research that proves this ” mode “, they can’t because there isn’t any. I have not been able to find a single one, but I can point you studies on fasting showing no reduction in your metabolism even after 72 hours without food, not that I advise anyone going 72 hours without eating . What is true is that the less we weigh, the less we need to eat to keep losing, and the slower we lose, but there is no such thing as starvation mode, weight loss can slow down , but it does not stop, you only have to show pictures of people who are truly starving to prove that point.

      If you use your weekly calorie total, and have high calorie days on weekends and counter that with lower calorie days at other times in the week, you will have no problems, and you will lose weight. How do I know ? well that is exactly what has worked for me.

      As I am fond of saying, the diet and fitness industry love to try and make weight loss complicated and confusing, but it honestly isn’t. It is simple… not easy, but it is simple, we just have to eat less, and find a way of eating less that we find easy to do. In my case that is using intermittent fasting to give me those low calorie days.

  • Lisa Meyer

    Thank you, thank you, thank you. It all makes sense now. Personally I love IF because it is easy to follow. I don’t like 3 small meals. It’s so much more enjoyable to eat a normal meal without stress. Thanks again for all the info.

  • Rebecca

    Hi Dave, i’ve been fasting 24hrs twice a week for a month and i’ve been losing 2lbs/week steadily. however after the weekend (i fasted on friday), i went up 1lb. is this fluctuation normal? just for the record, my time of the month is a week away…does that make a difference? (sorry if its TMI)

    • Dave

      Hi Rebecca,

      Yes it would make a difference, I will be the first to admit , we Men have it easier ;) . If over time your are trending down, that is what matters, so if at the end of January, you are lower than the end of December, and so on, you know everything is fine. Also as time goes on, you weight loss will slow down, that even 2lbs per weeks may be too much. Again, as long as you are losing month on month, that is all that matters. You are doing great, so just keep going !

  • Lillie Duncan

    Hi Dave. I am completely new to fasting. So new I havent even started yet. :)

    I am 5’7″ and 124. I feel my best at 115- 118 but have had the hardest time these past two years getting back to that point! I am a nutrition fanatic and addicted to exercise and count my calories religiously…and I dont know what gives bc I cant down to my goal weight.

    I want to try fasting. I read a couple ways to do it: the 24 hour fast (2x a week) and then have seen the 18-19 daily fasting. Which do you recommend?

    My BMR is 1391. So do I just multiple that x7 and then subtract how many pounds I want to lose in a week from that number? I know it sounds like a silly and maybe obvious question but I want and need to try something that will work for me.

    Thank you for your time and post!

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