I've gained 30lbs this year by eating a lot and training a lot. Now I want to put on another 20lbs by the end of the year. To be sure that I'm not increasing my body fat percentage, I'm trying to plan meals carefully.

When I enter my weight, age, and activity level into some of these online macro calculators, it spits out different amounts of macros depending on whether or not I want to gain or maintain:

149g protein
113g fats
445g carbs ~52%
total calories: 3,389

165g protein
99g fat
354g carbs ~47%
total calories: 2,965

I understand the general role of carbs in providing energy, and protein in building muscle... but I'm curious about:

1) Why the ratios change a little between Gain vs Maintain

2) Are these amounts determined through objective, scientific means? Or is this method just a "best guess" because of the debates over carbs vs fat / the meaning of a "calorie" / etc?

  • One could suggest you two very different plans for each scenario and could be also right. Carbs provide energy, but they can be also converted into fat or into certain amino acids (proteins) in your body, including the muscle proteins. Proteins can provide energy or can be converted to fat or can be incorporated into the proteins in the muscle.
    – Jan
    Aug 5, 2019 at 13:45

2 Answers 2


Echoing some of what David already said, much of this is an educated guess and everyone is different.

In regards to the ratios changing, dietary protein demands to maintain lean mass will decrease as total calories increase. So protein goes down (18% of calories) as calories go up in the gaining scenario you present above.

Grams of fat and carbs go up in the gaining scenario as the total calories are increased and the extra calories have to come from somewhere. When calories are at or below maintenance protein demands will increase... So in the maintenance scenario grams of protein are increased (22% of calories) while grams of carbs and fat are decreased as the caloric intake needs to be reduced and the deficit has to come from someplace.

You did not mention you weight or age (or if you did I missed it). However, this amount of protein seems a bit low as a percentage of total caloric intake. You are spot on in looking to gain quality weight. As stated above though, this is largely just educated guesses and based on the individual.

  • Log what you eat and take great notes.
  • Measure progress on the scale.
  • Measure your flexed bicep.
  • Watch how denim/blue jeans fit out of the dryer.

Putting the info above to work for you to gain mostly lean mass.

If the scale is going up and your jeans fit out of the dryer you are gaining mostly lean mass. It is working. Consider bumping calories a bit higher. If the scale goes up and the jeans are getting tighter you are gaining fat and lean mass. Consider dropping calories a bit.

When it comes time to lean out... if the scale is dropping the flexed bicep is remaining unchanged and the denim fit great you will be losing mostly fat mass and retaining lean mass.

Good luck!

  • thanks! I'm 32 - 178lbs right now. Should my bicep be measured when cool? Or after working out? There's a noticeable difference on arm day.
    – JacobIRR
    Aug 5, 2019 at 20:07
  • 1
    Measure cold same day of the week and time.
    – Ray
    Aug 5, 2019 at 21:15

Yes, these amounts are very likely determined through what is just a "best guess". There's no consensus on what is an optimal macro split for any particular goal, only guidelines, and what is truly optimal is likely to vary from person to person, and will be very difficult to determine with any accuracy. So these calculators do the best they can, which is choosing an algorithm that gives results that are probably reasonable for most people.

As for why the ratios change from gain to maintain phases, that's an artifact of their algorithm, which appears to work as follows:

  1. Estimate the user's lean body weight from their total body weight and age.
  2. Estimate the user's total daily energy expenditure from their body weight, age and activity level.
  3. Add the desired caloric surplus or deficit to get their target daily caloric intake.
  4. Assign 30% of their daily caloric intake to fat.
  5. Determine their daily protein intake target as a proportion of either their lean body weight or total body weight, with a higher proportion used for when they're not in a caloric surplus, in order to minimise muscle loss. (E.g. Maybe you entered that you are 75kg, and it used 2g/kg protein during gaining or 2.2g/kg during maintenance, to get the 149g and 165g targets for those respectively.)
  6. Subtract the calories assigned to fat and protein from the target daily caloric intake, and assign carbohydrates to meet the remainder.

So the reasons why the ratios change are that the amount of protein is calculated relative to your body weight rather than your TDEE (and the ratio changes in different phases), and carbohydrates are chosen last, resulting in there being no constant ratio of fat:carbs or carbs:TDEE.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.