"BURNING" FAT EXPLAINED
- Moran Sciamama-Saghiv
- Sep 24, 2023
- 5 min read
Updated: Nov 10
WHAT A BIG POST THIS IS!

One of clients' most sought out physical goals is to lose weight or as it is termed in slang (short for "soldiers' language) - to "burn fat". The idea of "burning fat" originates from the knowledge that when fat reacts with oxygen, a combustion reaction occurs, releasing energy in the form of light or heat. It is similar (not identical) to putting a good piece of meet full of fat on the grill, and seeing those flames get bigger, and perhaps a bit of a combustion reaction seconds prior. Am I making you hungry? - this post is definitely food for thought...
Very surprisingly, losing weight is extremely easy and fast. Easier and faster than you could ever imagine (unless you know physics...). According to physics, weight is calculated or estimated as the object's, tissue's, or person's mass multiplied by the local force of gravity. For example, a person will basically weigh 1/6 their weight on Earth, if they travel to the moon (assuming no major changes to weight on the way to the moon), since the moon's gravity is approximately 1/6 of that of Earth.
Now that we understand mass, gravity, and how weight is created, we can also very easily understand how fast we can lose weight. Simply spit, urinate, poop, clip your nails, cut your hair, shave your body hair, etc. and you have lost weight. Wait, did you mean reduce the extent of fat tissue (adipose tissue) when you said "lose weight" or "burn fat"???
Oh, I get it now. Well, that is a whole different story! - In such a case, you would have to convince and even force the body to use fat as the main fuel (substrate) for energy production. This by itself, is much trickier and complex, also does not happen too easily or fast as losing non-fat related body weight.
fat becomes the dominant source for energy production when movement pace is minimal and the time allocated to oxygen delivery, extraction, and utilization is long enough, and/or when metabolic circumstances allow sufficient oxygen content in the active cells, and/or when metabolic circumstances do not dictate the use of other metabolic fuels first. Starting to sound complex and "iffy"?
Commonly, the use of fat as the dominant source for energy production occurs after 60 - 88 minutes of continuous aerobic activity or exercise. Moran, is that a typo? - for a second there I thought you wrote that "the use of fat as the dominant source for energy production occurs after 60 - 80+ minutes of continuous aerobic activity"....Well my beloved subscribers, I DID!
You know why? - because sadly and realistically, it is true.
Energy production at the first 4 second of activities use recently produced ATP molecules that are repurposed, followed by 8-10 seconds of energy dominantly produced by the phosphagen anaerobic metabolic pathway. The next period of time up to 120 seconds from the beginning of the activity is governed by energy production via anaerobic breakdown of carbs (anaerobic glycolysis), followed by the aerobic breakdown of carbs (aerobic glycolysis) up to the 60 - 88 minute mark of the activity, and only then does fat become the main source for energy production, and we "burn fat".
Do not make the mistake of thinking that fat is not used prior, simply that it is not the dominant fuel for the creation of ATP. Fat is always used to create energy, yet there is a difference (a big difference) between how much fat is used at any given time. I guess we have already acquired enough knowledge to understand that exercise is NOT the best way to lose fat mass, yet it is important to exercise in order to support and increase the effectiveness of a fat-loss oriented diet, and in order to promote a healthy lifestyle, that in turn increases the number and extent of health benefits gained as a result of being active and/or fit.
The fastest way to lose fat (realistically, not being sarcastic) is to not consume it. Fat not eaten is fat not needed to be burned. Easier said than done, in most cases. Shoutout to all foodies!!! While the combination of exercise, physical activity, and proper diet (please use the services of professional dietitians!) is by far the winner option (not just for losing weight or burning fat), if you truly have a limited budget, invest it in the professional services of a licensed dietitian to create a personalized dietary plan, tailored to your specific and unique needs and goals. Don't use someone else's dietary plan because it worked for them. Then be physically active and get fit, using multiple free options.
Without getting into in-depth mathematical calculations, and the physiological basis to these calculations (see the post about estimating energy expenditure), every pound of fat (0.45 Kg; 450 grams; 15.5 oz) includes the energy worth of about 3,500 kilocalories (Kcal; big calories; large calories). In order to catabolize (breakdown; "burn") this amount of fat, a person must utilized about 725 litters (same as 725,000 mL; or 196 American gallons; or 191 Imperial gallons) of Oxygen.
Without getting into in-depth mathematical calculations, and the physiological basis to these calculations (see the post about estimating energy expenditure), a person will consume one pound of fat every two days if the rest completely the entire time without consuming anything with a caloric value greater the zero. Of course, this means starving your body, which will cause it to store fat more at first (counter intuitively to what most people would think and expect).
Another way to increase energy expenditure (investment) is to digest food and substances that the cost of digesting them is greater than their caloric value. To respect professional best practices, and the professionalism of other healthcare provider (i.e. dietitians), I will mentioned that this is commonly achieved by eating green leafy foods, and no more.
Services by Dr. Moran Sciamama Saghiv:
Tags associated with this blog post:
metabolism, metabolic rate, basal metabolic rate, BMR, resting metabolic rate, RMR, catabolism, anabolism, metabolic pathways, energy balance, energy metabolism, calorie burn, caloric intake, energy expenditure, ATP production, cellular respiration, glycolysis, Krebs cycle, citric acid cycle, oxidative phosphorylation, electron transport chain, aerobic metabolism, anaerobic metabolism, fat metabolism, carbohydrate metabolism, protein metabolism, metabolic health, metabolic function, metabolic rate increase, metabolism boost, slow metabolism, fast metabolism, metabolic adaptation, metabolic flexibility, hormonal regulation, thyroid function, insulin sensitivity, glucose metabolism, blood sugar control, lipid metabolism, cholesterol synthesis, triglycerides, fatty acids, beta oxidation, gluconeogenesis, glycogen storage, glycogenolysis, creatine phosphate system, ATP-PC system, energy systems, calorie deficit, calorie surplus, nutrition and metabolism, diet and metabolism, metabolic response, thermic effect of food, TEF, metabolism and exercise, resting energy expenditure, physical activity, metabolism and age, metabolism and genetics, metabolism and hormones, metabolism and sleep, metabolism and stress, cortisol levels, metabolism and hydration, metabolism and body composition, lean muscle mass, fat mass, obesity, overweight, weight management, weight loss, fat loss, metabolic syndrome, insulin resistance, type 2 diabetes, mitochondrial function, oxidative stress, free radicals, antioxidant defense, cellular metabolism, enzyme activity, coenzymes, vitamins and metabolism, minerals and metabolism, metabolism research, metabolic rate testing, indirect calorimetry, nutrition science, exercise physiology, metabolic conditioning, metabolic training, HIIT metabolism, metabolic rate calculator, metabolic adaptation to diet, metabolic pathways in cells, energy conversion, human metabolism, physiology of metabolism, bioenergetics, biochemical processes, health and metabolism.






Comments