Understanding Metabolism
Metabolism
Are you aware that every day your body is constantly trying to balance energy consumption and energy expenditure? Consumption, or “calories in”, comes from the food we eat—fats, carbohydrates, proteins, and alcohol. Expenditure, or “calories out”, refers to the amount of calories required to maintain bodily functions (resting metabolic rate), daily physical activity, and the thermic effect of food (Seebohar 2002). In the state of energy balance, the amount of “calories in” is equal to the amount of “calories out” and weight is neither gained nor lost. Positive energy balance results in weight gain, and is when consumption exceeds expenditure. Negative energy balance is the opposite and results in weight loss.
E z itt elég általános, de érdemes szólni róla. A kalóriaegyensúlyt akkor érjük el, amikor a bevitt kalóra egyneló a kimenő kalória értékével. Vagyis:
Kalória BE (zsír, szénhidrát, protein, alkohol) egyenlő
Kalória KI (RMR, fizikai aktivitás, TEF).
Calculating this balance is simple in theory, but is more complicated than just addition and subtraction. It is easy to estimate the calories that you eat and determine the ratio and quantity of fat, carbohydrate, protein, fiber, and alcohol you consume in a given day. However, expenditure is much more complicated and there are many factors that people over-emphasize, under-emphasize, and don’t even consider.
A Kalória Be érték könnyen kiszámolható, de a Kalória KI már más tészta. Számos dolgot túlságosan kiemelnek, másokat nem nagyon vesznek figyelembe, egyeseket pedig meg sem említenek.
Such overemphasized factors include fad diets, calorie restriction (low-calorie diets), and exercise intensity. Many individuals underemphasize the role that weight training plays in increasing metabolism. Also, studies show that people overestimate their physical activity and underestimate how much they eat by 20%, but overweight people tend to underestimate their intake by as much as 40% (Lacy 2005 2). Hopefully this will clear up questions and myths about metabolism and help you see the bigger picture.
Túlságosan fontosnak tartják az emberek a rövid ideig tartó diéták, alacsony energiatartalmú értrendet és az edzés intenzitását. Alig figyelembe vett aspektus a nehéz súlyokkal végzett edzés. Valamint nincsenek az emberek tisztában saját energiafelvételükkel kapcsolatban.
A very small contributor to burning calories is attributed to digestion and is called the thermic effect of food (TEF). The thermic effect is proportional to the amount of calories consumed and depends on the amount of fat, carbohydrate, and protein in the meal. TEF is usually about 10% of the calories consumed, so for a meal of 500 calories, 50 calories are used for digestion. TEF is not an important factor in weight management and should not be focused on (Seebohar 2002). Burris recommends that individuals eat every 2-3 hours to control the body’s tendency to store fat (Burris, 2003).
Another topic to consider along with nutrition is the idea of metabolic typing. Some professionals suggest that individuals have different nutritional requirements based on their genetics. These requirements are described in types, such as Carb Type, Protein Type, and Mixed Type. The types are much more specific than the food guide pyramid, which does not account for individual demands (Hittner, 2004).
Itt az emberek metabolizmusának típusáról beszél. (fehérje, szénhidrát, vegyes típusú személyek). Nem tér ki erre, és nem is fogok ezzel törődni.Expending Energy
Energy is spent through physical activity, which consists of intentional exercise and regular daily activity. Physical activity provides 15-30% of your daily energy expenditure (depending on your lifestyle), and can lead to an increase in your resting metabolic rate, which accounts for the majority of energy expenditure in a given day. A few ways to increase physical activity include riding a bike or walking instead of driving or taking a bus, taking the stairs instead of the elevator, and parking in a spot far away from the entrance to a building.
A fizikai tevékenység felelős a személy energiafelhasználásának 15-30 százalékáért, és ez a fizikai tevékenység kihat az RMR-re, amely az energiafelhasználás legnagyobb hányadáért felelős.
Resting metabolic rate accounts for 60-75% of the calories individuals’ burn. RMR is the sum of all metabolic processes that maintain normal body functions (Seebohar 2002). A typical RMR for males is 1500-1800 calories a day and 1300-1600 for females. There are many factors that influence resting metabolic rate (RMR). Body weight is the most obvious one. A person with more body weight will have a higher RMR than a smaller one because their body needs more energy to support and sustain the extra weight. With this is mind, losing weight causes a decrease in RMR because there is less weight to support and the body may be trying to conserve energy if there fewer calories are consumed (Lacy 20051).
RMR (testi funkciók elvégzése) felelős a kalóriafelhasználás 60-75 %-áért, ezzel messze a legfontosabb faktor a kalóriafelhasználás területén. RMR-t befolyásoló tényező például a testsúly, minél nagyobb valaki, annál több energia kell annak fenntartásához. Tehát súlyvesztést követően csökken az RMR.
Potentially the greatest influence on metabolism comes from body composition. Muscle is more metabolically active than fat, burning 30-50 more calories than fat per pound per day. Therefore, weight gain due to an increase in fat mass will not affect RMR as much as an increase in muscle mass (Lacy 20051). Metabolism also declines about 2-3% every 10 years, largely due to a decrease in muscle mass. This decline can be offset with the adoption of a consistent weight training program. One side note, there are many ways to strength train to maintain metabolism other than the typical bodybuilding program, which is designed to increase muscle mass and bulk.
Intensity: Cardio vs Weight Training
Regarding exercise, metabolic rate depends on the type of exercise, duration, intensity, and environment. More important than mode (cardio vs weight training) is intensity. A temporary (ideiglenes) increase in metabolism occurs immediately after exercise and is called EPOC—excess post-exercise oxygen consumption. This EPOC is the bodies attempt to recover from an exercise session. EPOC rises with intensity level. However, most people do not work out at an intensity high enough to significantly affect EPOC (Lacy 20051). An intense weight training session can have the same effect as an intense sprint session; the point here is that jogging for 30 minutes at 60% of your VO2 max will have little lasting metabolic effect.
Az intenzitás maga fontosabb, mint az edzés fajtája. (kardio vagy sulyzós). Az edzést követően jelentkezik a megnövekedett, edzést követő oxigénfelhasználás (EPOC). AZ EPOC az a jelenség, mikor a test megpróbálja visszaszerezni az edzés után elhasznált oxigént, mert az edzés során több oxigént használt fel, mint szokásos. Az EPOC nő az intenzitással. És az a lényeg, hogy az alacsony intenzitású edzés (Vo2 max 60%-a) nem nagyon növeli meg a metabolizmust.
To improve resting metabolic rate (long-term), fat-free mass must be increased. Studies have shown that training programs designed to increase FFM have a significant effect on decreasing body fat by increasing RMR (McCoy 2001).
Az az edzés, amely növeli a zsírmentes tömeget (FFM), az RMR növelésével csökkenti a testzsírt. Ennek az eléréséhez jellemzően a súlyokkal végzett edzés vezet.
These are typically strength training programs. If you are starting a weight training program for the first time, you may see dramatic increases in strength within the first 4-6 weeks. This is primarily due to improvements in your intra-muscular coordination (similar to the improvements in accuracy you would get from throwing a baseball) (Lacy, 20052). A weight training program has to be implemented for a few months before you gain enough lean mass to change RMR. Many studies have shown that aerobic training has no affect on RMR (McCoy, 2001).
A fenti vizsgálat kimutatta, hogy az aerob edzés nincs hatással magára az RMR-re. Nem növeli meg annyira, hogy elinduljon a zsírégetés.
One particular study conducted by Wilmore, et.al in 1998 concluded that after 20 weeks of endurance training, there was no change in RMR, even when there were significant changes in VO2max and body composition (McCoy 2001). Aerobic training only contributes to daily caloric expenditure, which is important for weight reduction but it has little or no effect on RMR.
Szóval az aerob edzéssel csak az a bibi, hogy nem emeli meg a metabolizmust lényegesen. Azért fogynak vele az emberek, mert csak annyi kalóriát égetnek, amennyit az edzés alatt használnak fel. És mivel láttuk, hogy az edzés (fizikai tevékenység) a Kalória Ki értékének mindösszesen 15-30 %-áért felel, ezért nem lehet annyira hatékony, mint az az edzés, amely a metabolizmust dobja meg (súlyzós edzés, megnövekedett izomtömeg).
In conclusion, there are many factors to consider when trying to balance energy intake and expenditure. “Calories in” can easily be estimated, but “calories out” are more obscure. We burn calories by eating food and exercising, but mostly from our resting metabolism. Resting metabolism is affected by weight and muscle mass; the most efficient way to improve body composition (increase the amount of fat-free mass, decrease the amount of fat-mass) occurs through weight training. Aerobic training is an excellent way to decrease overall body weight and should not be neglected.
References:
Burris, Craig. “Truth in Nutrition II”. PTontheNET.
Hittner, Noah. “Metabolic Typing.” PTontheNET.
Lacy, Brigitte. “Metabolism Matters II – The Mechanics of Metabolism.” PTontheNET.
Lacy, Brigitte. “Metabolism Matters III – Myths and FAQ’s.” PTontheNET.
Seebohar, Bob. “The key to Weight Management: The Energy Balance Equation and RMR.” PTontheNET.
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