The Truth About Metabolism?

Bagi orang yang sangat mementingkan bentuk badan yang cantik dan langsing, perkataan kalori sangat sinonim dengan mereka.

Apakah yang dimaksudkan dengan kalori (calorie)?

Kalori ialah unit tenaga/haba yang biasanya dihasilkan daripada makanan yang dimakan, atau secara definisinya, kalori ialah tenaga yang diperlukan bagi meningkatkan suhu sesuatu jisim air sebanyak 1 darjah celsius. Unit bagi gram kalori ditulis cal dan bagi 1000 gram kalori ditulis kcal (atau Cal).

Jika kita makan bahan makanan berkalori tinggi, akan tinggi jugalah tenaga (cal) yang akan dihasilkan, dan jika kalori yang banyak ini tidak digunakan (dibakar) sepenuhnya atau melebihi keperluan badan, maka kalori ini akan bertukar menjadi tenaga tersimpan dalam bentuk lemak. Ini akan menambah kegemukan dan berat badan.

Pembakaran atau penggunaan kalori/tenaga dalam badan sangat berkait rapat dengan kadar metabolisme badan seseorang. Kadar metabolisme ialah kadar kalori dibakar semasa badan dalam keadaan rehat, dan ia dipengaruhi oleh kandungan otot dan lemak. Jika jumlah kandungan otot lebih tinggi daripada lemak, ini bermakna kadar metabolisme seseorang itu adalah tinggi. Sebaliknya, jika kandungan lemak lebih tinggi daripada otot, maka kadar metabolismenya dikatakan rendah. Namun begitu dengan diet yang tinggi protein, kadar metabolisme seseorang itu boleh ditingkatkan kerana badan memerlukan tenaga yang lebih untuk menghadamkan protein.

Kadar metabolisme seseorang itu ditentukan oleh beberapa faktor, termasuklah:1. Faktor genetik atau keturunan.2. Faktor cara hidup – termasuklah diet/pemakanan dan senaman/aktiviti fizikal yang lain.

3. Hormon tiroid – mengawalatur metabolisme badan, termasuk cepat atau lambatnya pembakaran kalori, kadar penyimpanan protein atau lemak. Terdapat dua keadaan ekstrim berkaitan dengan pengeluaran hormon tiroid, iaitu hipotiroidisme dan hipertiroidisme. Hipotiroidisme ialah keadaan di mana kelenjar tiroid kurang aktif mengeluarkan hormon tiroid menyebabkan kadar metabolisme menjadi perlahan dan ini menyebabkan berat badan bertambah. Bagi orang hipotiroidisme ini, walau makan sedikit, badan akan cepat naik di samping beberapa simptom lain seperti badan menggigil, rasa badan lemah dan tak bermaya, dsb. Hipertiroidisme pula ialah keadaan di mana kelenjar tiroid terlalu aktif mengeluarkan hormon tiroid, yang mana ia meningkatkan kadar metabolisme dan menyebabkan kurang berat badan kerana semua kalori terkumpul dibakar dengan cepat. Bagi orang hipertiroidisme pula, mereka lebih beruntung kerana boleh makan banyak dan tidak perlu risau tentang berat badan yang bertambah.

Oleh itu, bagi membakar kalori dengan cepat, kadar metabolisme badan perlu dipertingkatkan atau dipercepatkan. Di antara petua yang boleh diguna pakai bagi meningkatkan kadar metabolisme ialah dengan pengambilan kafein (sebagai perangsang), makanan berempah, dan menjalankan aktiviti fizikal yang lebih lasak kerana aktiviti fizikal ini menyumbang 30% kepada pembakaran kalori setiap hari.

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The Truth About Metabolism

Your metabolic rate is strongly influenced by your body composition. People with more muscle and less fat generally have a faster metabolic rate, while people with more fat and less muscle generally have a slower metabolic rate.

High protein diet can boost our metabolic rates. Studies have shown that the body requires more energy to process a high-protein diet — which means that as your body digests high-protein foods, your metabolic rate increases.

Men tend to have a higher metabolic rate than women because women have higher levels of fat tissue.

What is metabolism?

“Metabolism” refers to your body’s systems for using or converting energy. This includes breathing, digestion, the building of muscle, and the storage of fat, circulation of blood — anything that’s part of your body’s systems for converting energy into an activity you need to live. Metabolism involves two distinct types of processes: “anabolic” reactions, which involve building cellular structures and the storing of energy; and “catabolic” reactions, which involve breaking down molecules for energy.

What is metabolic rate?

Metabolism is often confused with metabolic rate, and the two terms are often used interchangeably. More accurately, “metabolic rate” is the speed of your metabolism, or the rate at which you burn calories.

Strictly speaking, “metabolic rate” is the rate at which you burn calories while your body is at rest — something that is more properly referred to as your “resting metabolic rate,” or, measured a slightly different way, your “basal metabolic rate.”

Your metabolism and metabolic rate are determined by a number of factors. Genes play an extremely important role; they’re one reason why some people can remain thin no matter how much they eat, while others have a tougher time shedding pounds. Lifestyle — particularly diet and exercise — can also play an important role. No matter what sort of metabolism you were born with, or how well you have been maintaining it, it’s likely to slow down as you grow older.

Which organ controls metabolism

Your thyroid regulates your metabolism, producing hormones that influence almost every aspect of how your body performs: how fast or slow you burn calories, when or whether you build proteins or store energy as fat, and how your body responds to other hormones.

Not surprisingly, disorders of the thyroid can cause problems for your metabolism. An underactive thyroid (“hypothyroidism”) produces fewer-than-normal thyroid hormones, causing a slower metabolism, and, consequently often causes weight gain. An overactive thyroid (“hyperthyroidism”), on the other hand, can cause the metabolism to speed up, often resulting in weight loss.

Strength training/exercise and metabolic rate

Strength training can help you lose weight by changing your metabolic rate.

Strength training can indeed help you lose weight by changing your metabolic rate. But there’s disagreement about how this works.

Some claim that by building muscle and trimming fat, strength training boosts your resting metabolic rate, helping you burn more calories just sitting still. But according to the American College of Sports Medicine, for most people, this won’t result in much weight loss. Instead, they say the main weight loss benefit is due to its effect on calories burned while doing strength training, or as a direct result, as your body burns calories building muscle.

As you age, you tend to lose muscle. This results in a metabolic rate that begins declining as early as your twenties — about 2% per decade.

Eating fewer than 1,200 calories per day makes your metabolic rate speed up. Diets that are too severe can prove self-defeating, in part because of their effect on metabolic rate, and dangerous. Studies have shown that people who eat less than 1,200 calories per day are likely to wind up with a slower metabolic rate — which, ironically, can make it more difficult to burn calories and lose weight. Even going too long between meals can slow metabolic rate. That’s why experts recommend eating a small healthy meal or snack every 2 to 3 hours. Plus, eating helps boost calorie burn as the body works to digest foods.

Caffeine is a stimulant — and so by definition, it increases your metabolic rate. This is why it is often an ingredient in weight loss diet supplements. Studies have shown that one cup of American coffee can increase metabolism by about 3% to 4% for a short period of time.

Some spicy foods can indeed raise your metabolic rate. In particular, hot peppers containing capsaicin are particularly stimulating to a metabolic process called thermogenesis, in which the body produces heat, thereby burning calories. But this effect is unlikely to be strong enough to help you lose weight. If that’s your goal, head to the gym — not the spice rack.

Many dietary supplements claim they can help you lose weight by boosting your metabolism. Buyer beware. Ephedra, a stimulant that can increase your blood pressure and heart rate, was banned by the FDA in 2004 because of mounting evidence of potentially fatal dangers. And other studies have found little evidence to support the claim that other metabolism booster supplements such as L-carnitine or bitter orange can help you lose weight.

Most doctors, nutritionists, and fitness trainers recommend that you boost your metabolism the old-fashioned way: through diet and exercise.

Your body has to work hard to maintain its optimal natural temperature. In cold weather, your metabolism is forced to speed up to keep your body warm. And in hot weather, your metabolism has to speed up to keep you cool. It has been estimated that people living in tropical climates have a resting metabolic rate that is 5% to 20% higher than people living in more temperate regions.

You burn more calories just maintaining your body’s vital processes than you do through physical exertion. In fact, 65% to 75% of the calories you burn in a day are burned by your metabolism in the process of maintaining your body’s basic vital processes. Physical activity contributes up to 30% of your total daily calorie burn and is still one of the best ways to boost your metabolic rate.

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