All you need to know about metabolism6 min read . Updated: 03 Mar 2014, 07:15 PM IST
So you can't make this the excuse for not losing weight
Is your metabolism responsible for the state of your health or your body weight? Going by the things I hear, it’s enemy No.1: “I’m overweight because at my age metabolism slows down"; “I can’t lose weight because of my thyroid"; “I’m a woman and our metabolism is slower than men"; “My parents are fat, it’s my genes that are slowing down my metabolism"; and “I have tried everything, I’m on a low-calorie diet, but I’m not losing weight because of my metabolism". And so on...
The truth is that everyone, whatever the gender, genetic make-up or age, can boost their metabolism, and by increasing the metabolic rate, lose weight without reducing their existing calorie intake.
For metabolism is the rate at which your body burns calories. Simple.
Most people associate “metabolism" with weight gain and loss, but it’s actually the process by which the body converts food into energy. Our body needs energy—even while it is at rest—for basic functions such as blood circulation, breathing and cell repair. This is called the resting metabolic rate (RMR) or basal metabolic rate (BMR). Up to 75% of the calories we consume every day are used by the body for RMR.
The remainder gives us the fuel needed for daily activities and helps with digestion. On an average, most adult women require 1,200 calories a day for RMR, and about 200-400 extra calories for daily activities; for men, it is about 1,300 calories for RMR and about 1,400-1,600 for activities. This number can go up depending on the type of physical activity. The surplus calories we consume are converted into fat and stored around our bellies, thighs and other parts of the body.
Now that we have the basics down, let’s see what influences metabolism and what you can or can’t do to change it.
After 25, the BMR drops by 5-10% each decade in both men and women. This is mostly because of the loss of muscle mass—muscles require more fuel to maintain than fat—so the ratio of fat to muscle in a person determines their RMR to a significant degree. People who continue to exercise regularly after 25 drop their RMR only 0.3% per decade, says The Gravity of Weight: A Clinical Guide to Weight Loss And Maintenance. So don’t blame age, get moving.
Fluctuations in this hormone can slow down your metabolism. The solution is to see a doctor and make sure your thyroid hormones are functioning optimally. Your doctor may add certain vitamins for optimal functioning, and may ask you to avoid certain foods like cabbage, broccoli and strawberries which interfere with the functioning of the thyroid gland.
Protein requires more energy to be digested and metabolized than carbohydrates or fats. Your body burns twice as many calories digesting high-protein foods than it does with other food groups. If you want to increase your metabolic rate, increase protein intake and correspondingly, go easy on carbohydrates and fats. Healthy sources of protein include lean beef, turkey, fish, chicken, tofu, nuts, beans, eggs and other dairy products.
Small, frequent meals
Eat every 2-3 hours. Long gaps between meals make your body go into starvation mode, which decrease metabolism to conserve energy. Eating small portions with 2- to 3-hour gaps keeps your metabolism spiked throughout.
Weight training is the best way to increase metabolism. The more muscle you build, the higher your RMR will be. Weightlifting and high-intensity Interval Training also burn more calories for a few hours after exercising than any other form of exercise.
Every pound (around 0.5kg) of muscle uses about six calories a day just to sustain itself, while each pound of fat burns only two calories daily, according to Claude Bouchard, a professor of genetics and nutrition at the Pennington Biomedical Research Center in the US.
Less than 7 hours of sleep can decrease the number of calories your body burns just while resting, which it does for basic necessities like pumping blood, breathing, etc.
According to a 2011 study reported in The American Journal of Clinical Nutrition, sleep loss can promote weight gain not just by boosting hunger but also by slowing the rate at which calories are burned. The study also showed that one night of sleep deprivation acutely reduces energy expenditure in healthy men, which suggests sleep contributes to the acute regulation of daytime energy expenditure, that is, metabolism in humans.
The body needs water to process calories. If you are even mildly dehydrated, your metabolism may slow down. Include fresh fruits and vegetables, which are full of fluid, rather than high-salt potato chips which cause dehydration. The European food safety authority recommends that women should drink 1.6 litres of fluid a day and men, about 2 litres. However, if you have diabetes or any heart condition, speak to your doctor first, for you may be advised less intake.
Coffee can help a short-term increase in metabolic rate, when had in moderation (four cups a day is described as moderate). Caffeine can help increase your endurance while you exercise, so you can work out longer and harder too. Do not overdo coffee consumption, as excess can cause acid reflux, insomnia, increased heartbeat, etc.
Drinking green tea or oolong tea offers the combined benefits of caffeine and catechins, substances shown to rev up the metabolism for a short period of time. It is safe to have a cup after every meal.
Five grams of Tabasco can increase metabolism for up to 2 hours after you are done eating. This is because of the presence of capsaicin, the ingredient that makes chillies hot. If you suffer from gastric ulcers, don’t consume any form of capsaicin.
Omega-3 fatty acids EPA and DHA, found only in fish oil, can dramatically boost your metabolism, which is why they are so commonly recommended by gym instructors. Fish oil increases levels of fat-burning enzymes and decreases levels of fat-storage enzymes in the body. Capsules containing at least 300mg of EPA and DHA total are best for increasing metabolism.
Eating fewer than 1,200 (if you’re a woman) or 1,800 (if you’re a man) calories a day make no sense for anyone hoping to quicken their metabolism. Although these diets may help you drop weight temporarily, this loss is mostly muscle, and not fat. The lower your muscle mass, the slower your metabolism. In the long run your body burns fewer calories and you end up gaining more weight, so it is best to avoid crash diets.
Vitamin D supplements
When you’re low in vitamin D, not only do you lose weight slowly, you also have high levels of the hormone ghrelin, which causes hunger. Since there are few dietary sources of this vitamin, get a test done to know the level of vitamin D in your body. If you are low, the doctor will put you on a supplement.
When you are stressed you activate the hormone cortisol. One of the functions of this hormone is to put your body in fat-conserving mode, so de-stress to regularize your metabolism.
Yes, you can inherit a slow metabolism from your parents, but that does not mean genes have to rule your fate. Exercise, drink plenty of water, eat more proteins—you can work at improving your RMR.
So before you go blaming your metabolism, look into these factors. Remember, a slow metabolism certainly isn’t your fate.
Vishakha Shivdasani is a Mumbai-based medical doctor with a fellowship in nutrition. She specializes in controlling diabetes, cholesterol and obesity.