Twelve Weeks to a 4-Hour Marathon, Fueled Gram by Gram

A 12-week marathon block at 154 lb planned in grams: creatine with or without loading, protein per meal, carb loading, the pre-race meal and gel count.

Twelve weeks out, the scale reads 154 lb, the training plan says 4:00 for the marathon, and two strength sessions a week sit between the runs. Nothing about the food is written down yet. This is where the plan starts: one body weight, one race, and the advice of the International Society of Sports Nutrition (ISSN) turned into grams. The Creatine Calculator for the strength side, the Protein Per Meal Calculator for every day of the block, and the Carb Loading Calculator for the last days before the start.

There is no runner with a name here and no invented race report. The case study follows the plan itself, in two versions, and every number below is what the calculators print for 154 lb.

The project: 12 weeks, 154 lb and a 4-hour marathon

The inputs fit in one table. Everything else in the article is computed from them.

Input	Value	Where it is used
Body weight	154 lb (69.9 kg)	every calculator, each dose is per kilogram
Goal	a marathon in 4:00	carbs per hour and gels on the course
Length of the block	12 weeks (84 days)	creatine and protein totals
Lifting	twice a week, next to the running	the reason creatine and protein are in the plan at all
Meals	3 to 6 a day, chosen per phase	protein per meal and carbs per meal
Products	creatine $30 per 500 g with a 5 g scoop, shake 25 g of protein per serving, gels 22 g of carbs	scoops, servings and gel count

Two versions of the plan run side by side through the whole block. Plan A takes the faster option at every fork: a creatine loading phase, a protein shake before bed, two days of heavy carb loading. Plan B takes the simpler one: a small daily creatine dose, four equal meals, three days of moderate loading. Neither is wrong. They just cost different amounts of powder, time and stomach space.

Week by week: what each calculator decided

Week 1: creatine, with or without a loading phase

The ISSN position stand on creatine gives two ways to fill the muscles. About 0.3 g per kilogram a day, or 4 × 5 g, for 5-7 days. Or 3 g a day for 28 days. Both end in the same place, so the choice is about speed.

At 154 lb the loading dose comes out at 21 g a day in four servings of 5.3 g, which is 1.1 scoops of 5 g each time. A 7-day load uses 147 g. The calculator adds a note, because 21 g is a hair above the 20 g most studies actually gave: the per-kilogram rule taken literally. Four 5 g scoops would be just as correct.

Plan B skips all of that. One 3 g serving a day, 0.6 of a scoop, 84 g in the first 28 days, and the same 3 g afterward.

Why week 1 and not later? Loading brings a short-term retention of about 0.5-1.0 L of water, which the ISSN describes as roughly matching the quick gain on the scale. In week 1 that is a curiosity. In race week it would mean a pound or two more on the scale right before 26.2 miles.

Creatine Calculator: 180 lb, a 7-day load at 24.5 g a day in four servings of 6.1 g, then 5 g a day, and a 500 g tub that lasts about 72 days

The tub line settles the shopping. With Plan A, a 500 g tub at $30 lasts about 77 days: 7 of loading and 70 at 5 g. The block has 84 days, so the tub runs dry a week before the race. With Plan B the same tub would last 166 days, well past the finish line.

Weeks 1 to 12: protein, split meal by meal

The daily total comes first: 1.6 g per kilogram, inside the ISSN range of 1.4-2.0 g for people who train, is 112 g at 154 lb. The question is how to cut it. A review by Schoenfeld and Aragon puts the per-meal target at 0.4 g per kilogram over at least four meals, with 0.55 g as the upper planning figure. At this weight that is 28 g and 38 g.

Plan B splits the day into four meals and lands exactly on the target, 28 g each. Three meals would give 37 g, still inside the range. Six small meals would give 19 g, and the calculator flags it: below the ISSN floor of 20 g per serving.

Plan A adds a casein shake before bed, the 30-40 g serving the ISSN describes for overnight muscle protein synthesis. And here the calculator caught something that is easy to miss. The bedtime serving comes out of the same 112 g. Thirty grams go to the shake, and the four meals drop to 20 g each, below the 28 g target. A 20 g post-workout meal is 0.8 of a serving of the 25 g shake.

Protein Per Meal Calculator: 180 lb at 2.0 g per kg, four meals of 33 g and 33 g before bed, the post-workout meal as 1.3 servings of a 25 g shake

The fix for Plan A is simple once it is visible. Either raise the day to 2.0 g per kilogram, which is 140 g and four meals of 35 g without the shake, or accept smaller meals on purpose. Over the 84 days both plans eat the same 9,408 g of protein. Only the shape of each day differs.

Weeks 10 to 12: carb loading, in three possible shapes

The ISSN nutrient timing position stand no longer asks for the old depletion phase. Training comes down for 3-4 days before the race, and on 1-3 of them carbs rise to 8-10 g per kilogram. At 154 lb that gives three realistic versions.

Loading version	Per loading day	Per meal	All loading days	Pre-race meal
1 day at 10 g/kg, 6 meals, 3 g/kg before	699 g	116 g	699 g	210 g
2 days at 10 g/kg, 5 meals, 2 g/kg before	699 g	140 g	1,397 g	140 g
3 days at 8 g/kg, 4 meals, 1 g/kg before	559 g	140 g	1,676 g	70 g

Plan A takes the middle row: two days of 699 g, five meals of 140 g, 1,397 g in total. Plan B takes the last row: three gentler days of 559 g in four meals, which, by coincidence of the arithmetic, also come to 140 g a meal. The one-day version packs the same 699 g into six meals of 116 g, and in this table it is paired with the largest pre-race meal, 210 g.

Is 699 g a lot? It is about twice what an ordinary training day at the low end of the ISSN range would be. That is the whole point of the exercise, and also why it stops after two or three days.

Race morning and the course

The pre-race meal comes a few hours before the start, at 1-4 g of carbs per kilogram. Plan A eats 140 g (2 g/kg), Plan B 70 g (1 g/kg). Which one fits is a question of what the stomach tolerates, and that is worth testing on a long run first. The ISSN ultra-marathon stand points to gut training for the same reason.

On the course both plans are identical. For an effort over 2 hours the calculator gives 30-90 g of carbs an hour. The upper end assumes a glucose and fructose mix, which the ISSN ultra-marathon stand describes as the way to reach about 90 g an hour. Over four hours that is 120-360 g. With 22 g gels, 1.4-4.1 gels an hour and 6-17 for the whole race. The ISSN advice is to take carbs in small amounts every 10-15 minutes, so the gel count is really a schedule.

Carb Loading Calculator: 154 lb, a 4:00 marathon, two days at 10 g per kg, 699 g a day in five meals of 140 g and 6 to 17 gels of 22 g

And if the race goes slower? At 4:30 the course needs 135-405 g, or 7-19 gels. Two extra gels in the pocket cost nothing and cover that case.

The full balance of the block

Here are both plans next to each other, from the first creatine scoop to the start line. The last row is the number that actually differs in race week: carbs eaten before the gun goes off.

Phase	Plan A: faster	Plan B: simpler	Difference
Creatine start	7 days at 21 g (4 × 5.3 g)	3 g a day for 28 days	full stores in a week vs about a month
Creatine after that	5 g a day	3 g a day	2 g a day
Creatine over 84 days	532 g, a second tub in week 12	252 g, one tub with 248 g left	280 g of powder
Creatine cost at $0.06 per gram	$31.92	$15.12	$16.80
Protein per day (1.6 g/kg)	112 g: 4 meals of 20 g and 30 g before bed	112 g: 4 meals of 28 g	same day, different split
Protein over 84 days	9,408 g	9,408 g	none
Carb loading	2 days at 699 g, 1,397 g	3 days at 559 g, 1,676 g	279 g
Pre-race meal	140 g (2 g/kg)	70 g (1 g/kg)	70 g
On the course (4:00)	120-360 g, 6-17 gels	120-360 g, 6-17 gels	none
Race-week carbs before the start	1,537 g	1,746 g	209 g

The creatine row is where the money goes. Plan A uses 532 g of powder, 147 g of loading and 77 days at 5 g, and needs a second tub in the final week. Plan B uses 252 g, half as much, for the same full stores after the first month. On carbs the two plans meet in the middle: Plan B eats 209 g more before the start, spread over one more day.

Four lessons from planning in grams

Lesson 1: put the loading week at the start, not near the race

Loading is the fast way to full creatine stores, and it is also the part of the plan that moves the scale. The 0.5-1.0 L of water the ISSN describes belongs in week 1, where nobody cares. With the daily maintenance dose after it, the stores stay full through race day, and even after stopping they take 4-6 weeks to drift back to baseline.

Lesson 2: a bedtime shake can quietly shrink four meals

Adding a serving does not add protein unless the daily total goes up with it. At 112 g a day, the 30 g shake turns four meals of 28 g into four meals of 20 g. The calculator shows the split before the first shake is mixed.

Lesson 3: carb loading is two or three days of portions, not one dinner

Seven hundred grams a day does not fit in a single pasta dinner. It fits in five meals of 140 g, or four of 140 g on the gentler three-day version. Planning the meals is the actual work of carb loading. The total is just arithmetic.

Lesson 4: the gel decides the gel count

The runner is fixed at 154 lb and 4:00, yet the number of gels still depends on the packet. With 22 g gels the range is 6-17. With a bigger gel the count drops, with a smaller one it climbs. Enter the carbs from the Nutrition Facts panel and the calculator does the division.

Starting the same 12 weeks again

With the numbers on the table, the order would change in one place: the protein split would be checked before buying a casein tub, not after. The creatine choice comes down to whether one month matters, and in a 12-week block it rarely does, so the simpler 3 g start wins on cost and on the scale. Carb loading stays where it is, but the meals for those two or three days get written down a week early, in grams, because 140 g per meal is easy to underestimate with a plate in front of you. With the grams written down, the whole block fits on one page.

Not medical advice. The doses above follow the ISSN position stands for healthy adults who train. With kidney disease, diabetes, a digestive condition, during pregnancy or under 18, the plan is set by a doctor or a dietitian.

Tools discussed in this article

Creatine Calculator - loading and maintenance doses from body weight, each serving in scoops, and how long a tub lasts and what it costs.
Protein Per Meal Calculator - the daily protein split into meals and an optional bedtime serving, checked against 0.4 and 0.55 g per kg per meal.
Carb Loading Calculator - carbs per day and per meal for 1-3 loading days, the pre-race meal, carbs per hour on the course and the number of gels.