10,000 Calories challenge: how many kilos of fat in a day ?!

nutrition Jul 19, 2021

10,000 Calories challenge: how many kilos of fat in a day ?!

Admit it: who has never dreamed of eating at will for a day? Without limit, without frustration, whatever makes you want. You know, the old fantasy of being locked up at night in a supermarket and eating whatever comes your way until the early hours of the morning.

In this article we will discuss the impact of excessive calorie consumption as part of a one-time event. This is often what happens during a large family meal (religious festivals, weddings, all-you-can-eat buffet, etc.). To make this article more interactive and stick even more to reality, we will use the practical case of Antoine Fombonne who took up the famous Youtube challenge of 10,000 Kcal in Bangkok by ingesting 10,000 calories in just one and same day!

What are the variables to take into account to calculate the impact of the challenge:

Total Daily Energy Expenditure (TDEE)

It is the energy burned by the body in a day taking into account the Basal Metabolic Rate (BMR), physical activity and the energy necessary for the absorption of nutrients (the thermal effect of food = TEF ).

How to calculate the Daily Energy Expenditure (DEJ):

DEJ = Basal Metabolic Rate (BMR) + Physical Activity (PA) + TEF (+ Sports Activity)

The higher your DEJ, the smaller the surplus will be since the caloric surplus will be:

Calorie surplus = Calorie intake (10,000 kcal) - DEJ

Calculation of the TMB:

It is the energy necessary for the body to ensure its vital functioning, excluding physical activity and movement, as if you were lying on a bed without moving all day. There are many ways to calculate the TMB.

If you know an individual's body fat level, I recommend using the Katch-McArdle formula, which will probably be the most accurate. Katch-McArdle takes into account the percentage of body fat to evaluate the basal metabolism and thus avoids the overestimations which one finds in the formulas which only take into account the weight and the height. According to this approach, the MB is calculated as follows:

Katch-McArdle:

TMB = 370 + (21.6 x Lean mass)

Where “Lean mass” = Weight - (percentage of body fat x weight).

Otherwise, the Mifflin-St Jeor formula also provides a reasonable estimate:

Mifflin-St Jeor:

For men :

TMB = 9.99 x weight (kg) + 6.25 x height (cm) - 4.92 x age (years) + 5;

For women :

TMB = 9.99 x weight (kg) + 6.25 x height (cm) - 4.92 x age (years) - 161.

Calculation of physical activity:

This activity will depend on the individual, his professional activity and / or his lifestyle. Let's say if you are working sitting in a desk behind a computer, and even if you have daily physical activity, we can consider you to be sedentary!

Thermal effect of food:

The thermal effect of food (TEF) is the proportion of food energy intake that your body burns to metabolize these same foods. On average and according to the scientific literature, the TEF is often considered to be constant at 10%. However, the TEF varies widely depending on how easily the body collects energy from food. For example, a snake that swallows its prey whole, can have an TEF of up to 687% . To put it simply, the more complicated the food you eat for your body to digest, the higher your TEF will be. Complicated in the sense that it therefore requires more energy for digestion.

In humans, the variation in TEF is more modest: ranging from 10% up to 25% depending on the percentage of body fat, tolerance to carbohydrates and type of food.

2.) Initial body composition

The initial physical condition of an individual and more particularly his percentage of fat mass will determine his chances of storing more or less fat. The lower an individual's body fat percentage, the less fat cells, also called adipocytes, will be. He will therefore potentially have less chance of storing as much fat as an overweight individual with more adipocytes.

An obese individual will have up to 4 times more adipocytes than an individual with a lower body fat percentage. It will therefore potentially be less inclined to store fat, at least in the short term.

3.) Level of depletion of energy stores (glycogen)

The lower the energy reserves, the more your body will favor the repletion of glycogen stores before storing a caloric surplus.

Before an excessive consumption of calories it will therefore be interesting to train in order to empty as much as possible the stocks of glycogen, history to minimize the storage of caloric surplus in the form of fat.

4.) Calorie surplus macronutrient composition

The following research observes 2 groups within the framework of a caloric overconsumption of 50% compared to their optimal intake.The surplus was made up of carbohydrates on the one hand and lipids on the other. The results show that on the first day, in the case of carbohydrates, only 10% of the surplus was stored as fat compared to 60% for lipids. The following days the difference between carbohydrates and lipids decreases rapidly. This corresponds to what is already known on the subject, lipogenesis (conversion of carbohydrates into lipids) not being the main way of fat storage in humans. What happens is that consuming too much carbohydrate over the long term tends to suppress fat oxidation leaving more fat available for storage as fat.

Potentially, as part of a one-time calorie excess, it will be necessary to focus on carbohydrates in order to minimize storage in the form of fat. The more lipids there are, the more likely you will have it to be stored directly as fat.

5.) Individual's predisposition to increased thermogenesis (NEAT)

Non-Exercise Activity Thermogenesis, also known as NEAT (for Non-Exercise Activity Thermogenesis) is the energy expended on anything that does not include sleep, food, or athletic activity.

NEAT can be just getting a little more restless, wiggling your legs a little more when you're seated, or just walking a little more during the day.

In some particularly “agitated” people, the NEAT may be up to 10 times higher than the average. The following research shows that under a daily calorie surplus of 1000 kcal, energy expenditure in the form of NEAT ranged from -98kcal to + 692kcal depending on the individual. Which shows that we respond differently to a calorie surplus. Some people will move less, while others will burn up to 70% of the excess calories without thinking about it.

How many extra pounds for the 10,000 calorie challenge? The calculation:

We will estimate the impact of such a challenge by calculating it in 2 different ways. For the first method, we will use the physical data of Antoine, and in the second we will rely on the research cited below. We can then compare the two to estimate Antoine's fat intake during the challenge.

Method 1: Standard calculation

Under the conditions of the challenge:

Antoine / 27 years / 176 cm / ~ 11% body fat
10,000 calories consumed
Antoine's DEJ:
- TMB (Katch-McArdle) = 1716 kcal
- Sports activity: 2 training sessions (~ 140 minutes) = 813 kcal. This total is intentionally estimated broadly.
- TEF = ~ 20% (Antoine is an individual with a fairly low percentage of body fat, and he has an optimal protein intake, which places him in a high value in terms of TEF)
- Low physical activity: Apart from his sporting activity, Antoine generally has a sedentary type of physical activity. On the day of the challenge he actually walked 22,000 steps, which was integrated into his sporting activity. In addition, the energy expenditure of the two training sessions having been widely estimated, we can consider his level of activity outside training as sedentary. (Note in this regard that as a general rule, taking 3,000 steps a day to fetch bread does not make you an active person)

DEJ = Basal Metabolic Rate (BMR) + Physical Activity (PA) + TEF (+ Sports Activity)

DEJ = (1716 + 813) x (1 + 20%)

DEJ = 3034 kcal

Knowing that Antoine consumed 10,000 kcal over the day, the surplus is therefore 10,000 - 3034 = 6966

Impact of the TEF on the surplus:

The thermal effect of food will also apply to the surplus that is consumed by Antoine, since all the food consumed will be assimilated by his body.

TEF impact = 6966 x 20% = 1393 kcal

So 1393 kcal is the energy lost in the form of heat.

Impact of the increase in NEAT:

As we have seen in the following research , consuming more food generally produces an increase in NEAT. However, in this study, calorie overconsumption was daily over a period of 8 weeks. The average being 256 kcal ( see diagrams ) and our practical case applying only to a single day, let's remain conservative and estimate that Antoine burned an additional 150 kcal per 1000 kcal

Which gives us:

-150 kcal per 1000 additional kcal = 6966 x 150/1000 = 1045 kcal

We therefore have 6966 - 1393 (TEF) - 1045 (NEAT) = 4528 kcal available for storage as fat.

According to the following research and assuming that in the context of a punctual overconsumption, proteins and carbohydrates will participate to a lesser extent in fat gain, we can assume that 50% of the remaining calories will be stored as fat.

Or 50% of 4528 kcal = 2264 kcal which is equivalent to 252 grams of fat (1 gram of fat = 9 Kcal).

According to our calculation, Antoine will therefore have taken 252 grams of fat in a single day.

Method 2: Calculation based on calorie surplus research:

We can extrapolate the results of the research stated above in order to arrive in a simpler way to an estimate of its fat gain.

In this research where the subjects had a daily calorie overconsumption of 50%, the researchers then measured what percentage of the extra calories were stored as fat.

As you can see on the first day, subjects consuming a calorie surplus made up of fat stored 60% of the additional calories compared to 10% for those consuming carbohydrates.

Assuming that Antoine's calorie surplus was made up of an equivalent ratio of carbohydrate to fat, we can estimate that he stored around 35% of the extra calories, which is an average of research results (between 10 and 60%)

The calculation:

10,000 - 3034 (DEJ) = 6966 kcal

35% of 6966 kcal = 2438 kcal

2438 kcal is equivalent to 271 grams of fat.

Conclusion:

From the 2 calculations above, we can estimate that Antoine gained between 252gr and 271gr of fat in the space of a day at the end of this challenge.

So if for some it seems little, I remind you that visually, it remains quite impressive.

The image below represents 500gr of fat.

How much calorie is actually absorbed by the body?

A misconception that often comes up in the context of overconsumption of calories would be that the body is not able to absorb all these calories at once and that the surplus simply passes into the intestine until evacuated via the stool.

Yet there is no reason to believe, the calorie absorption capacity is only limited by the rate of absorption of transporters in the small intestine. And even if these transporters do indeed have maximum absorption rates ( around 60g / hour for glucose for example ) it should be borne in mind that digestion slows down in the case of such a caloric intake.

So if you are wondering if a huge intake of carbohydrates (Carb refeed) can be completely absorbed, the absorption capacity of the human gut has been estimated to be around 5400 grams per day for glucose, and 4800 grams per day. for fructose, so you will need to consume well over 20,000 calories before you get the “benefit” from malabsorption.

How to limit fat intake?

In order to limit your fat gain after occasional overconsumption of calories (weekend with friends, wedding dinner) or following such a challenge, the simplest strategy is to increase your physical activity on the same day. and to create a sufficient calorie deficit the following days. This is the strategy adopted by Antoine on the day of his challenge, since he trained twice during the day.

And to find out if he has managed to maintain a sufficient calorie deficit over the following days and limit breakage, I invite you to take a look at the video in which he takes stock of his challenge of 10,000 calories. :

And the video of the challenge!

Thank you for taking the time to read this article, and see you soon!

Science bro, not science bro.

#FitnessLogik

Related research and references:

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10,000 Calories challenge: how many kilos of fat in a day ?!