A diet record of a computer scientist who succeeded in losing about 15 kg by understanding the energy in the body as a 'battery'



Andrei Karpathy, a computer scientist and former Tesla employee who said he had no interest in health, exercise, diet, or nutrition for the rest of his life.What did he eat, what kind of exercise did he do, and how did he go from 90 kg to 75 kg? We explain why it was dropped from a technological perspective.

Biohacking Lite

http://karpathy.github.io/2020/06/11/biohacking-lite/

Throughout his life, Mr. Karpathy had no interest in health or diet, and only had a vague understanding that exercise and eating vegetables were good things. In June 2019, Mr. Karpathy found out that his weight was around 200 pounds (about 90 kg) and decided to reduce his weight to 175 pounds (about 79 kg), which is the appropriate weight. Before starting the diet, she first started researching biochemistry and energy.

Karpathy compares fat and energy to a battery, explaining that ``gaining weight is like overcharging your iPhone battery.'' Just as we provide power beyond a full charge, humans may eat to exceed our stored energy. This is exactly what overcharging means, and if you continue to store energy, it will naturally lead to weight gain.

Energy in living organisms is stored in ATP (adenosine triphosphate). When energy is consumed, ATP is hydrolyzed into ADP (adenosine diphosphate) and phosphoric acid, and when energy is stored, phosphoric acid combines with ADP and becomes ATP again. This mechanism can be said to be similar to the charging and discharging of a battery, but according to Mr. Karpathy, the battery system in the body can be broadly divided into four parts.



◆1: Ultra short-term battery
Only a small amount of energy can be obtained from ATP, and during intense exercise, a large amount of ATP must be repeatedly combined and decomposed. Therefore, during particularly intense exercise, the energy storage substance ``creatine phosphate'' is quickly decomposed to produce phosphoric acid, which helps quickly resynthesize ADP into ATP. Although this creatine phosphate can be charged quickly, it only operates for a short period of time, which Karpathy describes as an ultra-short-lived battery.

◆2: Short-term battery
The glycolytic pathway, which synthesizes ATP during the process of breaking down glycogen or glucose, is a short-term battery. Approximately 120 grams of polysaccharides such as glucose can be stored in the liver and approximately 400 grams in skeletal muscles, providing a total of approximately 2000 kcal, but the energy density per mass is not very high.

◆3: Long-term battery
Fat can be said to be a high-density, ultra-large capacity battery pack, with the highest energy density and capacity in the body. For example, it is estimated that 18 kg of Mr. Karpathy's 90 kg body weight is fat, which means that 162,000 kcal is stored here. If you convert it into fat alone, it's enough to keep you running for 81 days straight, and if you convert it into dynamite, it's the equivalent of 678 sticks of dynamite.

◆4: Other than fat
During prolonged fasting, your body may primarily burn muscle for energy. It is a battery that the body uses as a “last resort” when it is in a state of starvation.



These four batteries are constantly being charged and discharged in different amounts. For example, if you have just eaten a cookie, the cookie is quickly broken down into glucose, circulates in the blood, and enters a state of discharge readiness, and if the glucose is high, it is stored as glycogen in the liver and skeletal muscles, or if converted to fat.

When consuming energy, using the analogy of jogging, the 'very short-term battery' is mainly used for the first 3 seconds, the 'short-term battery' is used anaerobically for the next 8 to 10 seconds, and then the heart rate and If the respiratory rate increases and the amount of oxygen transported increases, the ``short-term battery'' and ``long-term battery'' will be used aerobically.



'I'm a computer scientist, so I compare the mechanics of how batteries are used to computer systems,' Karpathy said. 'For example, moving energy is similar to moving bits around in a chip. The ``very short-term battery'' is the L1/L2 cache, which is local, immediate, but small.The ``short-term battery'' of anaerobic respiration is RAM, and the ``long-term battery'' of aerobic respiration is ``Battery'' is a disk.The latency is long, but the throughput is high and the storage capacity is large.'' Next, I explained how energy is consumed.

Human energy metabolism is very simple, and energy can only be obtained by breaking down food. The actions that consume energy are complex, and it is consumed not only by exercise but also by everything necessary for life activities, such as heartbeat, breathing, and brain activity. The amount of energy required to sustain life is called the basal metabolic rate, and it is consumed for free even if you sleep all day. For example, Mr. Karpathy's basal metabolic rate is around 1,800 kcal per day. This is an extraordinary number, considering that just a few hundred calories of exercise can make you out of breath.



To summarize, the amount of charge is the amount of energy consumed minus the amount of energy consumed (basal metabolic rate + amount of exercise), and if the amount of charge is negative, weight will decrease. Having understood this far, Mr. Karpathy then devised a practical diet method.

Karpathy didn't want to go through a weight loss process that would make him stressed or hungry. I set a weight loss of about 1.5 kg per week as a goal that I think I can achieve. This means that you can achieve your goal by reducing the amount of charging by approximately 500 kcal per day.

To lose weight, Karpathy went on a low-carbohydrate diet. Karpathy cut out nearly all sugar and processed foods, avoiding carbohydrate-rich foods that quickly break down into sugar, eating plant foods like apples and bananas, and drinking drinks like soda, orange juice and alcohol. Implemented a diet of not drinking.



Additionally, I started doing regular aerobic exercise several times a week, as well as resistance training that puts stress on my muscles. As a result of doing it for a year while regularly slacking off, it seems that his weight decreased from 90 kg to about 75 kg. The following is a graph showing the change in Mr. Karpathy's weight, which shows that he has decreased by about 0.26 kg per week since the 120th day when he started reducing his life by 500 kcal a day.



'Overall, by reducing an average of 500 calories per day, I lost 15 kg in one year,' says Karpathy. 'More importantly, I learned to 'recharge' my ATP, which gives me extra energy. It is stored in the body as fat, so you have to reduce your intake or waste and discharge some of your energy through exercise to lose weight.Studying topics like this on your own can be a lot of fun. I did,” he concluded.

in Junk Food, Posted by log1p_kr