I briefly touched on the calorie math of the Potato Hack in a post back in 2015. In this post, I will be heading to the chalkboard to show my work and teach you how to figure out your numbers.
Before we begin, the Potato Hack is about creating a calorie deficit because it is REALLY hard to eat as many potatoes as you would need to meet your base caloric needs. In my example, all potatoes are boiled and then refrigerated overnight.
Photo by inove manore
#1 Get Your Base Metabolic Rate
There are a few methods used to calculate BMR. On this page, MyFitnessPal uses the Mifflin-St. Jeor formula.
I started my current potato hack at an even 200 pounds (my height 6 feet 2.5 inches). This gave me 1850 calories.
Bodybuilding.com has a calculator that uses the Harris-Benedict formula.
Using this formula, my BMR is 1937 calories.
Neither of these formulas asked me what percent of my weight was lean muscle or fat. The Sterling-Pasmore formula uses that information. That formula is:
- BMR= Lean body mass (lbs) x 13.8 calories
I haven’t had a body fat test in ages, but I’m going to guess 15% based on my past experiences. This gives me a BMR of 2346 calories
I don’t know which is more accurate. I’ll use the lower number of 1850 calories.
#2 Potato Math
A pound of cooked plain white potatoes is 350 calories according to The Potato Hack book.
According to Precision Nutrition, the average person will eat 3-4 pounds of food per day. The article What are your 4 pounds? does a great job going into this topic. I highly recommend this article.
People that struggle with body fat management tend to fill up on energy dense, processed foods. This means stored energy for later. In other words: extra body fat.
If we eat four pounds of whole, real food then we get lots of nutrition with a calorie count that our body can handle.
With the Potato Hack, our 4 pounds works out to just 1400 calories.
#3 Resistant Starch Goes to Work
Most of my potatoes consumed during the Potato Hack are placed in the refrigerator overnight. By cooling the potatoes, resistant starch is created and the calorie level is further reduced. With white rice, the calorie levels drop by 50%. With potatoes, it is approximately 17% (thanks, Tim Steele for doing the math).
So if we take 17% off the 1,400 we are down to 1162 calories.
For an explanation of resistant starch and why the calorie levels are lower read Chapter 9 of The Potato Hack: Weight Loss Simplified.
#4 Normal Activity Level
When I Potato Hack, I don’t lift weights. I also don’t stay immobile in a hospital bed. I still aim for 10,000 steps. To find the number of calories this burned, I discovered this helpful chart.
To use this chart, figure out your steps per mile. To get this number, I used my iPhone Health app. I took the monthly average for steps divided by the monthly average for miles. This gave me 2,142 steps per mile. Since I am closer to 2,200 than 2,000, I used the 2,200 step number for a 200-pound person. My average steps for the past 30 days were 10,925. Rounding up to 11,000, the chart says I’ve burned 545 calories.
I do recognize the 545 calorie number is under-reporting, as I am not tracking 100% of my movement. I’d rather underestimate than overestimate for this example.
BMR 1850 + Activity 545 = 2395 calories burned per day.
The Sterling-Pasmore Formula also has an exercise component.
- BMR x 1.375 for light exercise
- BMR x 1.55 for moderate exercise
I’m probably moderate, but I’ll split the difference (1.46) so my numbers err on the low side.
BMR (Sterling-Pasmore) 2346 * 1.46 = 3425 calories burned per day.
#5 Adding it All Up
Daily calories consumed = 1162
[A] Mifflin-St. Jeor Method
- Daily calories burned = 2395
- Caloric deficit = 1233
[B] Harris-Benedict Method
- Daily calories burned = 2482
- Caloric deficit = 1320
- Daily calories burned = 3425
- Caloric deficit = 2293
I have no clue which formula is correct, but they all demonstrate a significant reduction in calories. And with no hunger. Now multiply that loss across 3-5 days.
Check My Math
If I made any mistakes, leave a comment and I will update this post.
Before I end this post, I want to share another savings number. At this time of the year, I am paying $4.27 for a 15-pound bag of potatoes at the restaurant supply store. Many times of the year the price drops under $3. However, right now, I am paying 28.5 cents per pound of potatoes.
At 4 pounds per day, my total food bill per day of Potato Hacking is $1.14. During normal eating, I’m guessing I average $15 a day in groceries and taco trucks. For a daily savings of $13.86. During a 4-day Hack, I will save $55.44. And if I go for 5 days, I’ll save $99.30. Winning!
Aug 18, 2017 — 10:41 am
Taco trucks. You realize I’ve eaten nothing but spuds for 5 days now? Gotta go find me a taco truck!
Aug 18, 2017 — 2:31 pm
I was wondering if the refrigeration was to reduce palatibility, or to reduce calories by upping the resistant starch. Now I know.
It might be worth a try heating and cooling the potatoes a few times (each cycle allegedly increases RS) to see if it makes a noticeable difference in fat loss.
Aug 18, 2017 — 2:42 pm
Sorry, can’t join you this time around. Currently I am on a straight CICO kick, measuring everything, reactivated my MyFitnessPal account, doing weights as usual but also adding Heavy Hands walking. MyFitnessPal says I have a 1770 BMR, so I’m going with that. For inspiration I am readingthe fatlogic subreddit.
I’ll wait until the potato harvest this fall to do another round of Potato Hacking. Prices are not cheap where I live, and the potato harvest failed last year.
Aug 19, 2017 — 8:18 am
So with those steam bags of frozen rice you’re only absorbing %50 of those calories? Wow
Aug 19, 2017 — 10:36 am
@Stephen – I’m not sure if flash freezing will have the same effect as the 12 hour cooling period described in this article.
Aug 20, 2017 — 2:08 pm
What’s the current research on what happens to resistant starch levels if you re-heat the previously cooled rice/potatoes? As I recall, the last time I looked into it, the evidence was lacking or ambiguous.
Aug 20, 2017 — 6:31 pm
Resistant starch levels increase with each heating and cooling cycle, there is absolutely no doubt. Food processors use this knowledge to create RS3 products used in food manufacturing to add fiber to packaged foods. For instance, ActiStar RS3 is made by repeatedly heating and cooling tapioca starch until it increases from 5% to 80%. http://www.nutraceuticalsworld.com/issues/2004-10/view_suppliers-corner/-993742
Mar 12, 2018 — 10:19 am
In terms of calories you have “A pound of cooked plain white potatoes is 350 calories”. For clarity I am assuming that this is 1 lb raw weight not cooked weight?
Mar 12, 2018 — 5:18 pm
@Chris – Beats me. I can’t imagine that the calories between the cooked and raw version are much different. Probably a rounding error if there is a difference. Tim can correct me if I am mistaken.
Jul 24, 2018 — 6:46 am
Can you use the microwave to reheat or does it have to be the stove or oven?
Jul 24, 2018 — 7:14 am
@Angelina – The microwave is fine.
May 21, 2021 — 12:21 pm
Do you know if the cooking and 12 hr cooling would work for creating resistant starch in your oatmeal?
May 21, 2021 — 12:29 pm
@Mike – It appears so, but I don’t know to what degree.