Rethinking Calorie Reduction Needs In Weight Loss

If you’ve been around the weight loss world as long as I have and tried so many diets you’ve lost count, you likely know the standard weight loss equation.

One pound equals roughly 3,500 calories. In order to lose weight, you need to create a calorie reduction of about 3,500 calories either through a reduction in calories you consume, exercising more to burn additional calories, or a combination of the two.

Researchers at the National Institutes of Health in Bethesda, Maryland are now saying that that standard equation for weight loss may be wrong after all. Why? Because as you lose weight, your metabolism naturally slows down, making it less likely that you would automatically lose 1 pound when cutting out 3,500 calories.

An article on FoxNews indicated that lead researcher Kevin Hall has a new rule of thumb for weight loss.

The new rule says you need to cut 10 calories per day from your diet for every pound you want to lose over a three-year period. So cutting 100 calories per day will lead to a 10-pound weight loss over three years, Hall said. Half of this weight loss would occur over the first year. To lose more weight after the three-year period, you’d have to cut more calories.

I did the math, and under the standard equation, cutting 100 calories from your diet each day would theoretically cause you to lose about one pound a month, or about 10 – 12 pounds a year. Under the newer formula, the researchers are indicating that an 100-calorie reduction would only lead to a 5 pound weight loss the first year, and about 2.5 pounds of weight loss each of the next two years.

Now, I’m not going to argue with a researcher who has much more education than I ever will, but I do question whether this newer rule of thumb will hold up over the long run. Under their assumptions, reducing your calories by 500 per day would not result in losing about 1 pound each week, but instead losing only .5 pounds a week. Instead of losing about 50 pounds in a year as was previously thought, you would only lose about 25 pounds in a year – or half of the weight loss expected under the old way of thinking.

I am the first to say that weight loss is very fluid and changes from month to month even with the same person. I also know that everyone is different in how their body responds to calorie reductions. I wanted to get your opinions about how cutting calories has affected your weight loss.

For me, although I didn’t count calories, I know that I reduced my calories by at least 1,000 a day (Remember I was eating well over 3,000 calories each day before I started losing.) I saw a much more rapid weight loss than this new research said I should have.

How about you? Even if you are not a calorie counter, what has your experience been, or do you think this new formula is more true for you?  Diane

57 thoughts on “Rethinking Calorie Reduction Needs In Weight Loss

  1. Deniz says:

    I’m right there with you in that the ‘calories in, calories out’ mantra is only one aspect of successful weight loss. Things can, and indeed do, vary for the same person from week to week because other factors also play a part.

    I do agree that the first year of weight loss tends to see the most in terms of loss per week/month, but it sounds a little conservative that a 5lb loss is all that can reasonably be expected by creating a daily 100 calorie deficit. I actually find it quite a discouraging statement (and researchers are not infallible!). From reading blogs over several years, I think most people tend to see a little more than that, although we also see plateaus now and again.

    I guess the best advice is, as ever, to reduce calorific intake, increase energy use (move!) and think of weight loss as an ongoing, permanent lifestyle change not a quick fix.

    • Diane Carbonell says:

      That variation is what makes each of us unique isn’t it. I thought that the 5 pound loss seemed very small as well. And as Susan pointed out below, it would also be very depressing to lose that small amount. On the other hand though, cutting out 100 calories a day really isn’t that much. Less than an ounce of chips has about 100 calories. I like your last paragraph – great advice!

  2. Miz says:

    for me it is 100% what KIND OF calories too.
    when I first tried to find my healthy living path I consumed a lot of calories of the fat free variety and lost some weight but gained lottsa body fat.
    when I finally found what worked for me it ended up high calorie but of the variety my body responds to.


  3. Holly says:

    This formula has always confused me a bit. I know a lot of people who believe in the “calorie in, calorie out” formula. And I do as well for the most part. It’s just that I’ve seen in my own life that there is something else at play other than that. I know for a fact there are times when I have a serious cut in calories and yet my body holds onto the weight. That’s when I’m told by some that I need to up my caloric intake and actually eat more to lose. I think the issue is not as cut and dry as we’d like it to be. I do think that this new formula is kind of discouraging!! The one thing I just hold onto is that if I keep plugging away at this, the weight will come off. It may be slowly at times but eventually if I keep doing what I’m doing then the scale will keep going down. I’ll have to admit you’re a lot better at math than me!! I was confused on their calculations from the get go!! lol

    • Diane Carbonell says:

      Every person is different in how their body works. You are wise to not worry about the formula too much and just work on getting to your healthy weight. Slow weight loss isn’t a bad thing at all – in fact most medical professionals seem to point to slow weight loss as weight loss that sticks better for the long term.

  4. Jane at Keeping the Pounds off says:

    I do count calories but not with the expectation that I will lose weight. I count calories because I have the same amount (between 1300 and 1500) every day and if I do not count them I will usually over shoot the mark. I know eating this amount with my metabolism I will either stay where I am or lose more, depending on the make up of the calories. If my carbs are at 150 gms a day, I stay the same. If the carbs are lower, I tend to lose. If the sodium is high – stay. Fat stays between 30 and 50 gms a day and I can stay or lose. If it goes up, so do it. Exercise does not let me eat more. If I work out heavily for 2 hours I do not get to eat dessert as a reward. It does not work that way – not if I want it to still be working week after month after year.
    at least, that has been my experience.

    • Diane Carbonell says:

      It is very easy to overshoot the calorie mark. Believe me I know what you are talking about! You are so wise to be able to pinpoint what macronutrients do to your body, how sodium affects you, and what calorie level works for you. I showed my husband your website the other day and his jaw dropped!

  5. Diandra says:

    I think the “real” scientific formula is a bit more complex t han that. But the idea that weight loss slows down because one is getting lighter is not all that weird.

  6. Jody - Fit at 54 says:

    Maybe they took into account that people underestimate what they eat & they don’t log everything! 😉

    I think I better read more about this before giving an opinion but it is harder to lose the lighter we are & the closer we are but I will read more!

  7. Dr. J says:

    I am like you, Diane, as I never “count” but rather eat less. I think this is another reason that exercise must be part of the math for weight loss.

    I’ve read several different thoughts on calorie numbers. Some people feel that because dieting is hard, it’s a good idea to really cut back to low calorie numbers, especially in the beginning so we get results that are motivating. In my opinion, this is all right if you can do it. I am not a big believer in starvation mode, etc, but then I don’t look for excuses to fail. I look for reasons to succeed.

  8. Karen@WaistingTime says:

    I’ve long shared my thinking that the “math” doesn’t add up for me. I have attributed it to a few things and I may be right or I may be wrong. In my mind, having all my yo-yo dieting has wreaked havoc on my metabolism so my body hangs on tight to every pound. Also, seems to me I am much more sensitive to certain foods, like grains, so for me all calories don’t seem to be created equal. I do think that the smaller we are the harder it is and the slower our metabolisms so this might make sense. And then there’s the aging variable too.

    • Diane Carbonell says:

      Ah – that aging variable. That’s the one I don’t like right now. Even though it took me a long time to get to the point where I was emotionally ready to lose weight, those years of obesity and constant dieting gave me a lot of knowledge about weight loss, etc. That knowledge helped me immensely. When you add self-knowledge into the mix, everything seems to make more sense in how your body loses and maintains weight.

  9. Lisa @ Fat Chick Fed Up says:

    Ugh. I count calories faithfully. I have been doing this on My Fitness Pal ever since I started to get serious about my weight-loss about 8 months ago. According to MFP, eating 1500 calories a day with NO extra activity is enough for me to lose 2 pounds a week. Uh yeah, MFP is totally wrong and the weeks where I see a 2 pound weight loss are few and far between and when they do come it’s usually because I’ve made some drastic changes like cutting out all carbs or starting a new exercise regimin. Either way, it’s frustrating to say the least. My weight-loss has been VERY slow. I have lost almost 40 pounds, but in the same amount of time my husband has lost 100!!! I guess I don’t have an opinion nor am I qualified to speak to the validity of the research. What I know is my personal experience and my personal experience sucks. Just this past week I had a 2,6 pound loss on the scale. However the very next day I was up 2 of those pounds-not having made any changes, being under my calorie goal every day and exercising every day (which is something new for me). So needless to say, I am very frustrated because I am doing all the RIGHT things, and not making much progress. And there are people like my husband and others I have seen who consistently, week after week, lose big numbers and make steady progress. Mine has not been like that and I don’t know what to do about it. Like what is it about me that makes it SO hard to lose weight? I mean, I know it’s hard, but why does it seem harder for me than most? I just don’t get it because I can do all the same things that someone else does and I don’t see near the results that they do. I’m very confused.

    • Kaitie says:

      I deal with the same issue Lisa!
      For two years I have been doing the “right things” (exercise consistently, extremely specific, healthy diet) with almost not results. It is frustrating, confusing, and at times very depressing. I deal with it by setting little goals not related to my actual weight – run a mile, fit into my skinny jeans, trying a new kind of exercise for a week…

      Keep in mind that while you aren’t seeing the exact results you want, you are doing great things for yourself and your health!! Don’t give up!!

    • Diane Carbonell says:

      @Lisa – I feel your pain! I just wanted to encourage you to not compare your weight loss journey to your hubby’s or anyone elses. The fact that you’ve lost 40 pounds is amazing and I applaud you for that! I know that slow weight loss can be frustrating but consider the alternative. No weight loss?!

      It sounds like daily weigh-ins are frustrating for you (and you are not alone). Perhaps weighing less frequently would help you feel less tied to the scale. Look for those non-scale victories like feeling more energy, clothes fitting lower, having more control over your food choices, being able to do something you weren’t able to before.

      One piece of advice? Don’t give up. Like Dr. J said “Look for reasons to succeed.” You can do this and are proving to yourself that you can!

  10. Gina (The Candid RD) says:

    Thanks for stopping by my blog!
    Good for you for coming such a long way on your weight loss journey, you look great and from this blog I can tell you are a true inspiration. Thanks for this post, as a dietitian I am well aware that the old recommendation of “cutting calories by 3500 per week will get you to lose 1 pound a week” is OFF a bit. I mean, it just sounds too easy, and clearly it doens’t work that way. I hadn’t heard of this new equation….I need to look into it further, clearly! I’m not much for calorie counting. I feel that it causes more stress than is necessary.

    • Diane Carbonell says:

      You are welcome! Thanks for your insight and taking the time to come over! Calorie counting is stressful to me. Especially when I would forget what I ate earlier in the day, didn’t want to admit that I had the whole bag of chips, or realized that I had already met my quota by 2:00 p.m.

  11. Sharon says:

    Like others, I’d like to know more about this new theory before stating an opinion, but the one thing that struck me immediately was the mental aspect. With concentrated effort, losing an average of only two pounds per month would be (or would have been) devastating to my emotional journey. I never wanted to have unreasonable (or miraculous) expectations of what I would lose, but any less than an average of one pound per week would’ve never been sustainable, because the discouragement factor would’ve kicked in totally. And I only had 65 pounds to lose. Can’t imagine how that would’ve felt to any of my peers looking at 100+ pounds.

    • Diane Carbonell says:

      I agree with you. If I had only lost 2 pounds a month I would have quit. Especially when I weighed 300 pounds. My weight fluctuated that much day to day. Great point about the discouragement factor. (I like that term.) So often people do feel discouraged, and rightly so. For me, that’s where this kind of research can have value in terms of education and understanding why the weight loss slows and finding ways to kick it in gear again.

  12. KCLAnderson (Karen) says:

    I am one who believes in the validity of both science and “woo-woo” (for lack of a better word). I counted calories (as well as percentages of carbs, fat, and protein) for a while back in 2005-2006, and I do believe counting helped me understand the science and it helped me lose 55 pounds. That said, I regained…not because I stopped counting calories but because I wasn’t working on the emotional (“woo-woo”) component. Also? I hated counting calories…it’s not something that I can force myself to do. I am not a scientist.

    The “woo-woo” is what helps me be an emotionally healthy person, and being an emotionally healthy person is what helps me keep the weight off. The “woo-woo” also encompasses something that science is on the cusp of proving: the idea that while we’re all so very much the same in terms of DNA and all that kind of stuff, we’re also highly unique. It is our souls? And so we must honor our souls and not force ourselves into thinking that there’s only one way to approach our health.

    • Diane Carbonell says:

      Absolutely critical. I gave a talk at a university the other day and I told them, “In my 14 years of talking with thousands of people about weight loss, I have yet to meet someone who struggles with their weight that does not have some kind of emotional component to their weight issues.” As I explained to them – it doesn’t have to be a horrible, deep-dark secret, but the emotional component is huge.

  13. Babbalou says:

    My experience has been that I cannot lose a single pound if I eat a low fat high carb diet. I can lose, slowly, if I limit carbs. No calorie counting necessary, and no limitation on fat, although I generally prefer foods that aren’t very fatty. I eat a lot of vegetables. I know other people who have very different experiences, clearly it’s a lot more complicated than calories in and calories out. I used to have notebooks full of documented meals, with calorie counts by day and detailed notes on exercise done. According to the calculations, I should have been losing two pounds a week. I lost nothing over a two month period. To say it was frustrating doesn’t begin to describe it. And all the well-intentioned advice to eat less and exercise more made me cry, I was living on 1200-1600 calories a day and running five miles a day. Plus working full time, and taking care of my home and my family. I’m glad to see, gradually, a recognition that there’s more going on that a simple mathematical calculation

    • Diane Carbonell says:

      There is definitely more going on than just a math equation. If it really were an infallible calculation, everyone who wanted to could lose weight by just following a low-calorie diet until they hit their goal weight. Clearly that is not the case as you just aptly described. I’m sorry you had such frustration – it sounds like you have found the food combination/calorie level that works for you and I’m glad!

  14. E. Jane says:

    I’m so glad that you have started a discussion on this topic. I think it is all so confusing to those of us who are trying to lose weight that sometimes we give up. We’re all different, and what works for one person doesn’t work for another. I can lose weight without exercise if I stay at 1200 calories or less per day. In fact, I lose more weight at that level than I do at 1400 with 30 minutes of exercise. Exercise has never been a big help to me. Perhaps that’s because I don’t exercise at a high enough level. Anyway, I think that those of us who have been at this for a while learn what does and does not work for us, but it’s good to try and clarify the numbers. Thank you, Diane.

    • Diane Carbonell says:

      Thanks! When I read that article it really spoke to me. Why? I think because of just what you said. It can be a confusing process. A very overweight person really can lose weight fairly easily by cutting calories. But as she gets lighter, the process needs refining. The calorie level often needs adjusting, the exercise level may need to change, or the nutrient component may need to be tweaked. I hear the most frustration from people whose weight loss has stalled even though they are doing all the right things. That’s when you really have to find what works for you.

  15. Maren says:

    I count calories and make it pretty simple.. I stay below my “budget”, exercise, and just go with the flow. If I hit a long lasting plateau I’ll have to change things up. 🙂

    • Diane Carbonell says:

      And it is working for you! Calories do matter and when you reduce them to a weight loss level weight loss generally occurs! You are doing a wonderful job at being consistent and not giving up.

  16. Siobhan says:

    I think that the important thing is to find what works for you. Doesn’t matter who else is more right, just matters if what you do results in you losing weight.

    • Diane Carbonell says:

      The results do matter. Like my mom used to say, “The proof is in the pudding!” Each individual finds what works for them. When they do it all seems to fit together like a puzzle whose piece he or she finally found.

  17. Marie@feedingfive says:

    I am very mathematical so I get it, but honestly when it comes to the body it will never be an exact science. Also I think it is impossible to calorie count accurately, just my opinion. I did it for a while and it nearly drove me insane. When I think back about measuring vegetables I just shake my head. Why on earth would I limit vegetables just to meet a certain number? Insane.

    • Diane Carbonell says:

      I agree. It is not an exact science when you are losing or maintaining weight. Calorie counts on packaging may not be entirely accurate, and there has been study after study that shows that restaurant calorie numbers are often way off. Plus, there is human error when we measure foods or estimate how much we ate.

  18. Janis says:

    I think the formula is true when larger people first start out, and it becomes less so as they progress, but not necessarily because one’s “metabolism slows down” or anything — just because the body’s first resort when burning itself as a result of a calorie deficit is to go after the tissue that that “3500Cal/lb” describes: fat. There’s not 3500Cal in a lb of just ANY kind of tissue in the body. Per pound of bone? Per pound of muscle? Per pound of brain tissue?

    No, it’s 3500Cal/lb in FAT tissue.

    When you’re first starting out and you have a lot of fat to get through, your body will burn through it at that nice predictable rate. But after you have put a sizeable dent in your fat stores, your body will start burning through stuff that burns at a different rate. Or else you’ll have to start exercising harder because your body is done burning most of its fat stores, and you have to find another way to run through your excess calories. So I think it’s deceptive to say that the metabolism “slows down” or “starts working against you.” You’ve simply burnt through most of your fat after you have lost a good chunk of weight, and so your body starts in on tissue that burns at a different rate.

    • Diane Carbonell says:

      This is something I learned along the way too. I realized that while I might be able to lose weight eating 2,500 calories in the very beginning of my journey when I weighed 300 pounds, I had to adjust my calorie intake downward as I began to weigh less. By the end I was at about 1,200 to 1,500 calories I believe. Good point about the fat tissue and our bodies burning at a different rate as we lose weight. Plus, exercise plays a huge role in the weight loss process.

  19. MamaBearJune says:

    I also believe that not all calories are equal. 100 calories of candy vs 100 calories of nuts do NOT do the same things in your body. I started losing 1-2lbs a week when I changed WHAT I ate, not necessarily the calorie count.

  20. Lori says:

    There is something else at play. While we can count calories, the one thing we can really tell is water retention from weather, food, exercise, PMS, whatever. Also – unless you are in a completely controlled environment given a nutritional drink that has the calories exact, daily calorie counting is approximate at best.

    I also do find a difference on the scale for me when my daily calories are made up of different types of foods. Eating more fat and protein (particularly) and the scale goes down quicker for me.

    • Diane Carbonell says:

      There is a lot to it. What works for person A may not work at all for person B. I’ve seen that myself and I’m sure you have too. I’m lucky that carbohydrates don’t bother my weight loss/weight maintenance. Although I do have to say that I don’t eat white rice, white pasta, white bread, etc. I just eat whole wheat products.

  21. Taryl says:

    My experience has been a bit of both, actually. I definitely noticed the leveling off of maintenance, where my body got used to my new food intake and wasn’t losing at the same rate, even with the same percentage of deficit. I had to switch up my nutrients and activity to adjust it downward. And then ultimately, I had to do something more radical to break my floor of 192 or so, and get further down the scale. Now I’ve come full circle, where I am seeking energy balance and adjusting nutrients for optimal health while not moving the scale, and relyingo a completely different formula/method for reduction. And with maintaining, the calories are only a rough guide and what I eat, similar to Mizfit, is what makes all the difference.

    I think our metabolisms are complex and variable – and that makes ANY equation calculating their function a thing of massive generalizations and approximations 😉

    • Diane Carbonell says:

      It is a complex subject, which is why there is always research going on. I do believe the general 3,500 calories = 1 pound formula is basically correct, but there are sure to be variations on that formula for each individual. We are all different and our metabolisms work differently from each other depending on our age, gender, etc.

  22. Lisa says:

    I didn’t even bother with a formula. I had no idea I needed one. What I did know was that if I ate 2,000 calories or less a day I’d lose weight. Especially considering I was probably eating over 5,000 calories a day before! I lost the weight (110 pounds) just staying under 2,000. That was all it took.

  23. LovesCatsinCA says:


    This sounds right. I think people who are heavier to start with, lose a lot to start with because it’s easier to start that momentum–just like those pesky last 10 pounds are usually harder to lose. I don’t know anyone who loses exactly what the math says they should lose each week–sometimes you lose nothing, sometimes you lose 4 pounds all at once even though you theoretically shouldn’t from caloric reduction numbers. I think our metabolisms all differ anyway. Age, activity level, gender, muscle mass, etc.

    That formula sounds around right. I eat 75% of the calories I used to on average, to maintain a weight around 80% of my peak weight.

    The other thing about slowing one’s metabolism down has to do with restricting one’s calories consistently as opposed to burning more consistently. If one varies one’s diet so one day you eat 1,200 calories and one day you eat 1,800 and one day you eat 2,200 and you AVERAGE 1,500, and some days you walk for an hour and some days you do elliptical for 1/2 hour and another day you do elliptical for an hour, your body doesn’t get all accustomed to a single activity level/activity/caloric intake, etc.

    I’m more relaxed about overdoing it nowadays. I realized my body naturally is less hungry the day after a big caloric intake–and as long as I don’t consistently eat a lot more than what my body needs, it’s able to process a splurge and get back to equilibrium easily.

    • Diane Carbonell says:

      I know that was true for me. At 300 pounds, it wasn’t unusual for me to lose 20 pounds in the first month but the weight loss slowed the closer I got to goal. Good point about slowing your metabolic rate when constricting calories. I think there is truth in calorie cycling as you described because then your body doesn’t get used to just the same food, the same calories, and the same macronutrients every day.

  24. LovesCatsinCA says:

    PS the 1,500 average number is for someone like me–short/small frame/middleaged. If you’re tall or young or super active, it would be more normal to average 1,700, 1,800, even 2,000 plus calories… but I found out that 2,000 calories a day was okay as a 20 year old who exercised 3 or 4 hours a day. It’s not okay at almost 50 and averaging around 4 or 5 hours of exercise a week!

  25. Elizabeth says:

    I think the scientific research can be so confusing at times. I do believe in needing to cut more calories after a significant weight loss. Also, working out to burn calories is so important. I take counting calories by spells. When I am being really strict, I am more likely to count calories.

    • Diane Carbonell says:

      I know a lot of people who have had great success with calorie counting. It does work because you really can see not only how many calories you are consuming but where those calories are coming from. I developed a good “calorie awareness” when I was losing for the last time and that still helps me maintain. Working out is important – that was the one thing I did differently when i lost weight – worked out.

  26. nivedita says:

    I am still in the weight loss process, and have another 15 kgs to go before I enter the “normal weight ” realm. I have lost 20+ kgs till now. I noticed that my weight loss stalls when I consume carbohydrate in the form of wheat/rice more than once a day. Even when I am rigorously working out.
    Right now I consume 1300-1500 calories per day with working out about 5 times a week, including strength training and cardio. After reading your article, I wonder how much longer and how much lesser I should eat to achieve goal weight. Recently my weight loss stalled and going back to weight training has begun to push the scale in the downward direction.
    But yes. I record what I eat and exercise I get, and have begun to pay close attention to the way my body behaves, my energy levels, food cravings and basically have begun to listen to my body a lot better!! In the end, I think that is what is important!

    • Diane Carbonell says:

      I’m not a dietitian, but from my own experience as you lose weight it is natural for the process to slow down and even stall. It sounds like you are doing the right things with working out more and finding out what foods tend to help you lose. Carbohydrates never seemed to bother my weight loss. Your calorie intake is inline with what most medical professionals seem to recommend. I generally ate in that range because I did not want to starve myself. Paying attention to your body and what works for you is so important!

  27. Ayie says:

    Sometimes, it is not reliable to believe some of the scientific basis and explanations about this…We can learn from our experiences too…

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