Do You Need to Lose Weight?

Health — By 88DB Knowledge on October 17, 2011 1:24 pm

Shedding those extra kilos can reduce the risk of serious obesity-related diseases and make the difference between life and death, say experts.

Lose Weight

Shedding light

Losing weight is not just a cosmetic issue to do with looking good. For a rising number of people here, dropping a few kilograms could mean the difference between life and death. The proportion of obese adults here has grown from 6.9 per cent in 2004, to 10.8 per cent this year, the latest National Health Survey found.

Body mass index (BMI)

A person is of a healthy weight when his or her body mass index (BMI) is within the range of 18.5 to 24.9. He or she is overweight if it is between 25 and 29.9; and obese at 30 and above. The BMI, a measure of the amount of fat based on weight and height, is calculated by dividing a person’s weight in kilograms by the square of his or her height in metres.

A typical Singaporean woman has an average height of 1.62m and an average weight of 55kg, a National University of Singapore’s (NUS) Faculty of Engineering study on 315 of its students, which was published this year, found. So her BMI – calculated by dividing 55kg by the square of 1.62m – is 21.

The BMI of a typical Singaporean man, standing at 1.74m and weighing 68kg on average, is 22.5. If your BMI is 30 or more, you are more likely to get serious diseases like heart disease, stroke, diabetes and high blood pressure than someone whose BMI is below 25. For example, an obese woman with a BMI of 30 is 28 times more likely to develop diabetes than one whose BMI is 22.

Reducing weight greatly reduces the odds of getting these illnesses. For example, those at risk of coronary heart disease who lost a significant amount of weight reduced the risk of a heart attack, heart failure or death by up to 30 per cent.

When to shed pounds?

23 BMI People whose BMI is 23 and beyond should shed the pounds, doctors advised. Studies have shown that Asians tend to have more body fat than Caucasians of the same BMI, said Dr Ng Chung Sien, resident physician at Changi Sports Medicine Centre at Changi General Hospital. So even though an Asian with a BMI of 23 is not overweight, he has the same amount of fat and the same risk of developing an obesity-related disease as a Caucasian with a BMI of 25. Asians with a BMI of 23 to 27.4 are at moderate risk of obesity-related diseases, while those with a BMI of 27.5 or more are at high risk.

How much to lose?

Someone who is at moderate or high risk of obesity-related diseases must lose at least 5 per cent of his body weight to gain significant health benefits, doctors said. If they can lose more weight, the benefits will be greater, said Dr Ng. They are recommended to drop 1/2 to 1kg a week, through diet and exercise. This should help them shed enough weight to return to the healthy BMI range within six to nine months.

Losing too much weight too quickly could be a result of going on “fad diets” that are difficult to sustain and have unknown long-term effects on health, said an endocrinologist. For example, the Atkins diet, which recommends high protein intake and low intake of carbohydrates, would lead to quick weight loss. But high amounts of protein could, in the long run, raise the level of uric acid and cause kidney stones to form, he said.

Losing weight too fast may also be the result of excessive dieting and exercising, which carry health risks, said Dr Ng. Dieting excessively can lead to dizziness, stomach inflammation, menstrual irregularities, osteoporosis and depression; while over-exercising can cause dehydration, physical injuries such as torn ligaments, fatigue, insomnia and depression.

How to diet?

To achieve weight loss, one has to burn more calories than one eats. A kilogram of fat gives about 7,000 calories of energy. So to lose 1/2 to 1kg a week, one needs to eat 500 to 1,000 calories less than the amount expended daily, said a senior dietitian. This sum is deducted from the daily average energy requirement for a person, based on his age, gender and activity level, to help him lose weight, she said.

The Health Promotion Board recommends 2,500 calories a day for a man, and 2,050 calories a day for a woman, if they are aged 30 to 59 and have a light activity level. Generally, an average adult should eat about five to seven half-bowl servings of rice, about two to three palm-sized servings of meat, two small fruits and two servings of vegetables, with each about three-quarters of a cup.

To shave those calories off, reduce portions of food and limit intake of high-calorie food – such as fatty and sugary food and alcohol – to no more than twice a week. But one should still have a balanced diet with carbohydrates, protein, fat and fibre. One should also drink more water so as not to mistake thirst for hunger. Eating more fibre from fruits, vegetables and wholegrain foods could help a person feel full faster and for a longer time said a nutritionist. These are usually low in calories and can also help reduce the amount of calories consumed, she said.

How to exercise?

Healthy individuals need to exercise at moderate intensity for about 21/2 hours a week, with each session lasting at least 15 minutes, Dr Ng said. Those who want to lose weight should do moderate-intensity exercise for about 31/2 to 5 hours a week. Moderate intensity refers to having the heart pump at 50 to 70 per cent of its maximum rate, which is calculated by deducting one’s age from 220. As a rough gauge, an activity is of moderate intensity if you can still talk while doing it, Dr Ng said.

Aerobic exercises like brisk walking, jogging, cycling and swimming help people lose weight more quickly, he said. They can also dance and practise martial arts like muay thai, said a personal trainer. Start slowly with say, brisk walking for 30 minutes a day, three times a week, and then gradually increase either the duration or intensity over a few weeks. It is also important to add resistance training to one’s exercise routine to build muscle mass as increased muscle mass helps to raise the metabolic rate, thereby helping to burn calories faster.

Resistance training involves building up the strength of muscles by making the muscles work against an opposing force generated by weights, exercise machines or resistance bands. Dr Ng said that resistance training could be added twice a week, after some weight loss has been achieved. “Resistance training is part of weight loss exercise, but it’s not as effective as aerobic exercise. So in the initial period, and if you have no time, you may want to give priority to aerobics exercises,” he said.

Reproduced with permission from http://www.healthxchange.com.sg, Singapore Trusted Health & Lifestyle Portal.