Should I subtract fiber from My carbs? Let's break it down! - IIFYM

Should I subtract fiber from my carbs?


When it comes to IIFYM and fiber, there is no additional math. With IIFYM and weight loss, we base everything off of the gross amount of carbohydrates, not net carbs. Losing weight is all about the gross amount of food we eat, which is why there’s no reason to subtract fiber from carbs.

So, when you get your macros from the IIFYM calculator, keep this in mind so you’re focused on only the essential aspects.

Why You Don’t Subtract Fiber with IIFYM

If your macro diet dictates that hit 150 grams of carbs and 30 grams of fiber, you do just that. At the end of the day, on your weight loss log, make sure that you have eaten 150 grams of carbs and 30 grams of fiber.

  • Not 120 carbs and 30 fiber
  • Not 180 carbs and 30 fiber

If you care about weight loss, 30 grams of your carbs should be fiber, and they still count as calories (for our example).

IIFYM blueprint

The way your body digests your carbs is not of concern to us. The glycemic index of the carbs, nor the sugar content, nor the type of sugar is a concern. All we care about is the fiber content. So at the end of the day, just make sure that you hit your fiber and your carbs separately.

You will find, however, that since carbohydrates and fiber are connected, that this can be tricky at first. If you have a hard time getting all of your fiber in, you might want to try using a fiber supplement. Just be sure to log it, since there are calories in fiber and as you know. Calories = Fat gain if you are in a surplus!

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  • Emma

    As you have rightly said for fat loss it’s all about calories in vs calories out. Therefore can u please explain to me how you workout the amounts of calories that should be distributed or carbs and fats??
    Both can be used in the for energy so does that mean as long as you are within your caloric limit their division does not need to be stuck to as rigidly?

    • The calories are distributed in to the macros in a way that helps protein build or preserve muscle, carbs provide energy and recovery, and fats for hormone balance.. Calories in/out are the number 1 dictator of weight loss, but macros determine how much of your weight loss comes from fat or muscle.

      • Joshua


      • Joshua

        Today I will be hitting legs and will be hitting them hard. My Carb intake according to my macros is 160. Is there room for me to adjust or do I simply follow my macros?

      • Carlos

        Very simple and clear. Thank you!!!

      • hailey

        So since not all calories come from simply protein, fats, and carbs perfectly, if I find that I’m hitting my protein and fat goals, and getting close to my carb goal but my calories have already been reached, should I just take in less carbs? I feel like there’s sometimes just no room for calories to come from anything else and it won’t work out as perfectly as when I figured out what I should be eating.

      • Andy

        Hi, When you say split carbs and fibre and hit each macro separately – should a food label say 30g cho of which 5g fibre do i subtract the fibre g from the cho making it 25g and 5g fibre OR does it stay 30g and 5g?

        Thank you

  • Kari

    I am 1 week in counting my macros. I’ve noticed I tend to go over on my fiber. Should I be concerned with this and try to lower my fiber intake or is too much an okay thing when it comes to fiber?

    • How much are you going over? 10-20%?
      I would not worry about it.. More than that, and you may want to pull back slightly

      • Kari

        Most days about 10-15% over, one day I doubled it somehow.. thanks for the response.

        • I would not sweat it

  • Veronica

    I entered my info and the calculator says to have 29.5 g carbs and 36-45 g fiber. What should I do in this instance?

    • You are overweight to the point where all of your calories are getting burned up in the protein.
      Try using the lean mass formula where you enter your bf%
      That will make a big difference

  • Brandon T

    yesterday my total Carb was 62.08g and my fiber was 16.4g. When counting, do I say for the day I only had 45.68g of Carbs or do I still read my carbs as 62.08g even though they say fiber is digested totally different then a non fiber carb? You may have explained this but it wasn’t really clear enough for my understanding. Thank you!

    • You count what you ate. Not what you body digests..

      • Brandon T

        Understood, Thank you for the speedy response!!!!

  • NickR.

    I’ve always been confused by this: what percentage of carbohydrates need to be “complex” for example, NOT an Apple. Like, I’m supposed to get 400g carbs daily. How many of those carbs should come from pasta, rice, oats, bread etc…This has always confused me. For example, I could easily eat 100g of carbs from fruit or something of that sort. But I am never sure what amount of each carb to consume. COMPLEX VS FAST ACTING? Hope this mAkes sense and that you can understand what I’m asking. Again, for example, out of 400g of carbohydrates, how many of those or what ratio of those, need to be from complex carbs such as rice,bread,pasta,oats,potatoes etc….and how many can be from like fruit and things such as that like sugary type carbs….THANKS!

    • 100% of your carbs should come from carbs.
      Simple as that
      Forget about simple and complex. Just hit your macros and your will lose weight.
      Stop making it more complicated than it needs to be

    • Sterling

      You need to search up low-glycemic (slow acting) and high-glycemic (fast acting) foods. Carbs are carbs yes but I see what you’re trying to ask. There’s no “this amount for this food” cheat sheet for your diet. If you need more information about how much YOU should eat. Check out with a doctor who can tell you your glucose levels and go from there and then you’ll be able to tell yourself how much of oats you should eat or how much of wheat bread or ice cream. It’s more of an individual question that you’re trying to figure out. Ya know?

  • Kriz

    If i always hit my carb intake (in this moment is 269 gr cause im bulking.) But its very dificult to me to mantain my fiber intake in 23-29 gr per day, i tend to go over 40 gr. How could this affect my diet? Is this fiber surplus make fat?

    • No big deal- You can go up to 50 and still be fine.
      Just make sure you don’t go over on your carbs.

      • Kriz

        Ok perfect!! Thank u so much!! 😀

  • Ella

    If I go slightly over on my fat (only by about 5 grams) but under on my carbs does this balance it out?

  • Jordan

    How important is tracking fiber? The journal I have doesn’t have a spot for it so I’ve been ignoring it, but I’m planning on starting iifym

  • Jillian

    I am having trouble staying below my carb count, I am supposed to be eating around 102.3 a day and am well overshooting it. I find that most carbs come from things like fruit/veggies, but most things have some carbs in them. Do you have any food alternatives or suggestions to help lower my carb intake.

  • Kelly

    I just started tracking my macros about 3 weeks ago, in the first 2 weeks i dropped about 10lbs but then hit a lul just wondering how often you should make adjustments to the macros and how to tell if i should add or take out fats or carbs!

  • Taylor

    I’m finding Quest bars complicating. I understand you have explained that you count what you ate, not what you absorb, so would I factor in a Quest bar as 22grams of carbs, or calculate it as “3g net carbs”? Again, forgive me if this is a repetitive question, but considering I am a female who shouldn’t be going over 100grams of carbs a day, this would make a huge difference if I am eating more than required.
    Thank you!

    • You would factor said Quest bar in as 22g carbs. And enjoy every morsel.

  • David S

    What do you do about cereal boxes? They deduct fiber from their calorie counts, so should you add the missing calories back in? Fiber One says there are only 60 calories per serving, but they’ve deducted 14 grams (or 56 calories) worth of fiber carbs from the label. That should be 117 calories per serving rather than 60 as the label says. If I eat two servings per day to meet my fiber needs, that is a lot of calories that I’m not sure what to do with, and it’s screwing up my goals. What are you supposed to do?

  • Alexia

    Ive been making sure i get at least 20g fiber each day, but i use Psyllium husk as a supplement, the one i use says in 15g you get around 12g fiber, now my question is that it has <1g carbs in that amount of serving, but how can that be if you say carbs and fiber are connected? would like to hear some insight and see if maybe i am going over my carb count by using this (just incase it is wrong?) thank you

  • Aleen

    So in terms of counting macros on the fitness pal, would I use total carbs or net carbs for a protein bar? I am currently on a low carb diet. thank you

  • Sterling

    That’s a very controversial statement being made that fiber adds calories for overall carbs. There’s an article stating that fiber does not contribute to your total carbs or calories because there are not digested by the human body. They horoughly explains the connection between fiber and carbs and blood sugar. Definitely recommend reading.

    • Jhunt

      This is technically true but not completely true. The body does not digest fiber but b in the gut does in fact breakdown and utilize some of the fiber to carry on various functions. If weight loss is your goal then your recorded carb intake would be lower than your actual intake if you subtract fiber.

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