Guide to Determining Caloric and Macronutritional Needs

This is a guide written by Miles B Huff and intended to provide a comprehensive overview of figuring out your caloric and macronutritional needs.

Body composition

Get a DEXA scan. Everything else is just pulling guesses out its ass, and cannot be relied upon until you've had a DEXA scan and know how these simpler/cheaper/safer methods deviate from reality. Even your 3D gym scans (like Styku) are problematic; and in my case, my cheap Chinese electrical impedence scale was closer to my DEXA results than the fancy Styku scanner at my gym!

Protein

Formulas I created with the help of ChatGPT from the recommendations in Jeff Nippard's "The Ultimate Guide to Body Recomposition":

• Men: GramsOfProtein == (−1.5625 * BodyFatPercentage) + 1.7
• Women: GramsOfProtein == (−1.25 * BodyFatPercentage) + 1.7

(Important to note: BodyFatPercentage should be a decimal ratio out of 1. So 30% is 0.30.)
Once your have your value, multiply it by your lean mass to yield how much protein you need every day.

Derivation

Per Jeff Nippard's "The Ultimate Guide to Body Recomposition" (pages 97-101):
For protein, use a value derived from a linear interpolation and extrapolation of the following ratios:

• Men: 1.2:30%::1.6:5% or 1.2:30%::1.5:10%
• Women: 1.2:40%::1.6:8% or 1.2:40%::1.5:25%

The document is contradictory about which is correct, but it's likely the second female ratio (the one from the charts, not the one from figure 8B) was a mistake given how much of an outlier it is, and given how the document says to use the values in figure 8B. (Someone should inform Nippard of this discepancy.)

These ratios result in the following formulas:

• Men: GramsOfProtein == −1.6 * BodyFatPercentage + 1.68 or GramsOfProtein == −1.5 * BodyFatPercentage + 1.65
• Women: GramsOfProtein == −1.25 * BodyFatPercentage + 1.7 or GramsOfProtein == −2 * BodyFatPercentage + 2

(It would have been nice if Jeff had given us a formula so that none of this guesswork would be necessary.)

We can actually unify one of the terms, since it appears to be the same for both, surely only off by a small margin of error because of the different rounded-off fat percent ranges used: 1.68 and 1.70 can be unified to 1.69. Another option is to set them to 1.7, since this value is the grams of protein used at 0% bodyfat, and Jeff clearly intended to have only one significant digit in his grammage ranges. A final option is to set them to 1.6667 (repeating), which represents 5/3, a simpler/commoner ratio, and in-between the two ratios given for men above.
We can potentially go a step further, and try to ensure everything is in simple ratios. This would mean making the -1.6 of men be -1.5625 (which is in-between the two original formulas) so that it's a simpler deviation from the female -1.25 (exactly 25% higher).
This then yields the formulas above.

BMR

Get your BMR measured.

While you are waiting to get your BMR measured, you can try to estimate it using a calculator online. There are various formulas for this; they are all problematic. The main ones use total bodyweight without heed to composition, and the one that does pay heed to composition only looks at lean mass and ignores the rest. One way to attempt to mitigate the errors both approaches cause, is to average the results of Mifflin-StJeor and Katch-McArdle. However, always remember that these figures are imperfect. My own measured BMR is actually closest to the Revised Harris-Benedict formula, which is considered dated compared to the other two.

Get your BMR re-measured if you go through a major body recomposition.

Calorie target

Once you know your BMR, add Calories to it according to how much physical activity you undergo in a typical day. You want to get a good idea of how many Calories you burn, so that you know how much to eat to meet your goals. There are calculators online that can help you estimate this according to your activity level.
If you want to lose weight, reduce this Calorie amount by the number of Calories you want to lose each day; conversely, if you want to gain weight, increase it.
(It is worth noting that the body can handle some deviation in Calories in vs out without losing or gaining weight. This has two implications: One is that you don't need to hit your Calorie goals exactly every single day, and the other is that your caloric deficit or excess must be sufficiently extreme as to overwhelm this homeostasis.)

Fat & Carbs

Once you have your daily Calorie target, we can start figuring out your macros.
Multiply your optimal grams of protein by 4 to figure out how many Calories it amounts to.
Subtract that amount from your Calorie target.
Round to a simple target.

The remaining figure is to be divided between fat and carbs.
Fat should come first because it is an essential nutrient. Carbs should be consumed only if there is room in the Calorie budget left after fat. The body can live "forever" (until old age) without carbs, because it can create them from fats and proteins; the body cannot live "forever" without fat (It's super important.). Ideally, though, the body has ample access to both in the diet.

Fat

Per Jeff Nippard's "The Ultimate Guide to Body Recomposition" (pages 108-109), eat 1/5 to 1/3 of BMR* from fat. This should help ensure that you do not become deficient in fat-soluble vitamins and such.
Imho, unless you are carefully tracking micronutrients, you should try to aim for the upper-end of this range (1/3 of BMR), just to help ensure you get enough essential nutrients. This is a good idea anyway, because it means that less of your calories will come from carbs, which is an important consideration for those with insulin resistance.

Contentions

(I am using 1/3 (33.3333%) instead of Nippard's 35%. The 35% figure is likely a rough decimal approximation of the real figure, 1/3.)

*Nippard says "total Calories", not "BMR", and I disagree with him there. Afaik, your fat needs do not greatly differ according to additional energy expenditures or caloric restriction/surplus. You eat fat to get essential micronutrients, not to get energy; energy comes principally from carbs.

Yet Nippard suggests modifying how much fat you eat based on physical activity levels. Imho this is a hack to work around the fact that he is using the wrong comparator. When you target fat as a percentage of BMR and then get the percent of that target out of your total Calories, you find that this second percentage (the one Nippard takes as primary) adjusts itself automatically. So by using the correct comparator, we do not need Nippard's adjustments.

While we are talking about hacks, it is important to note that even the percent ranges themselves (1/5 to 1/3 of Calories) are just a very rough proxy for "Are you getting enough vitamins ADEK and essential fatty acids?", which is a question that can only be directly answered by auditing micronutrient intake, something which is inherently outside the scope of this discussion on macronutrients.

Nippard also suggests targeting lower fat intake at lower body fat percents than at higher bodyfat percents, but imho this is fraught/misguided given only the reasons he specifies. One minor reason he gives for why seems to be a conflation of low bodyfat and physical activity, which I must point out do not always go hand-in-hand. But his main reason -- that higher-fat individuals are less insulin-sensitive and therefore should eat less carbs, which can be achieved by getting more of your calories from fat -- while valid as a statement (non-carbs have essentially no glycemic index), is missing the big picture. Yes, fat people should eat less carbs; but filling that gap with more fat doesn't solve the fact that they are fat and insulin-resistant. What does solve that problem is losing the fat, which you can do by having a deeper Caloric restriction. And how do you get that safely/healthily? By eating less carbs. There are no necessary implications for fat intake here, and his extrapolation of this to skinny people, whereby he advises them to eat less fat, is illogical per these premises.

Carbs

To figure out how many carbs you can eat, subtract the values you got for protein and fats from your Calorie target.

Carbs are not evil! Your brain and body operate best when they have access to these. Your gut does, too: dietary fiber is conventionally a special kind of carbohydrate that the body can't directly utilize. Where carbs become problematic are when you regularly eat more fuel than your body needs, or when you regularly spike your blood sugar with simple carbohydrates. Think about it: You don't top off at the gas station because it's bad for your car's engine; so why are you filling your own tank completely past capacity? And you don't regularly hit your car's engine with N2O, so why are you eating so much sugar?

Wrap-up

Should you, in the future, wish to increase or decrease the calories in your diet, do so by increasing or decreasing carbs.
If there is no room for carbs in your diet, do so by increasing or decreasing fat between that 1/5 to 1/3 of BMR ratio.

Also, Nippard says deviations of ±10g for proteins and carbs and ±5g for fats are fine (page 30). Because his deviation for fat is half that of protein and carbs, these figures are surely derived from the Calories for each (because fat is about twice the Calories per gram as protein and carbs). Accordingly, these deviations can be expressed as a single figure in terms of Calories: ±40kcal.

Example profile (mine)

Meta:

• Age: 30.1yo
• Height: 6'0"

Body Composition: (from DEXA)

• Weight: 284.2lbs
• Fat: 104.1lbs (36.6291%)
• Lean Mass: 171.4lbs
• Measured BMR: 2460 kcal
• Estimated sedentary burn: 738 kcal
• Maintenance Calories: 3198 kcal

Protein:

• Grams of protein per pound of lean mass: 1.1277 g/lb
• Protein goal: 193g (193.2827g)

Calorie Goals:

• Target caloric expenditure: 2500 kcal
• Protein Calories: 775 kcal (773.1308)
• Non-Protein Calories: 1725 kcal
• Fat Calories: 825 kcal (820.0000) (33%)
• Carb Calories: 900 kcal

In my case, I can round these further to 800/800/800 for protein/fat/carbs, for a further 100 calorie reduction. This makes the protein slightly high, but still within Nippard's margin of error; and, in some sense, it helps semi-futureproof things as I recomp to have more muscle again, because my protein needs are only going to go up from here.
Note: Just because 800/800/800 seems optimal for me does not mean that it will be so for you. You should run these numbers for yourself, because everyone is different.

Outro

Now, interesting to note: I normally fall under my measured BMR in terms of Caloric intake, but I also am always very low on protein compared to what is optimal for me, and my sleep is consistently poor. There is more at-play in body recomposition than just nutrition (and there's more to nutrition than getting your macros right), and the Calorie Deficit Model doesn't explain everything (If it did, I wouldn't still be fat.). Nevertheless, this guide is a great place to start (or at least I hope it is! I write these things for myself, after-all.).

Some other high notes you'll want to be hitting are:

• Good sleep hygiene (If your sleep is off, your whole body is off-kilter before you even begin. Sleep needs to be solved before everything else. Best way to solve it is to go for a walk right after waking up every morning (assuming the Sun is up when you awaken) -- the Sun will set your Circadian rhythm to "morning", and then you'll get tired for free at the right time every night. In a cruel twist of fate, artificial light is insufficient to trigger this in the morning, but it is sufficient to trigger this in the evening. Dim, red lights located below your eyes can avoid this late-night stimulation; but don't block red light during the day -- blue light is important for signalling "daytime" to the brain! This podcast does a really great deep-dive on sleep protocol optimization.)
• Regular exercise (This is really important, and for reasons that mostly have nothing to do with weight loss!)
• Adequate UVB exposure (It's virtually impossible to get enough vitamin D through diet alone, and supplementing it at therapeutic levels has risks. You are designed to be outside some of the time; like everything, there's a balance. Too little and too much of any essential thing is bad for the body, and UVB is no different there. How much you need depends on your skin color, but for those with my light complexion, 10-15 minutes fully exposed to the midday sun is said to be sufficient; look up what your own skin color requires.).