SINGAPORE - People always ask housewife Chua Mui Hong, 50, if she is ill or has lost weight - and she dislikes it.
At 1.52m tall, her weight has never exceeded 40.5kg. She should weigh at least 42.7kg for a healthy body mass index (BMI) of 18.5, a measure of the amount of fat based on weight and height.
The mother of two grown-up children has been troubled by her lack of weight gain for the past 20years, but this is the first time she is making a New Year resolution to do something about it. She said: "I just want to put on weight. Any gain will do."
Doctors and traditional Chinese medicine practitioners have said there is nothing wrong with her and that she probably has a high metabolic rate.
During a health screening in September last year, Madam Chua was diagnosed with impaired glucose tolerance, also known as pre-diabetes.
It did not come as a total surprise, since both her parents, who are in their 70s, are diabetic.
She cut her carbohydrate and fruit intake to avoid spikes in her blood glucose level. To her dismay, she lost 1.5kg after three months and now weighs 39kg.
She said: "I'm struggling to put on weight but I'm forced to cut back on my food intake."
Each day, she has three main meals and four smaller ones. For breakfast, she has two slices of wholemeal bread with butter and a protein shake.
Lunch is usually a three-quarter bowl of porridge with vegetables and fish, or fried noodles.
At tea time, she has a snack - either a small boiled sweet potato, wholemeal biscuits, a handful of walnuts or a cup of oatmeal.
At 5.30pm, she has an early dinner - usually a bowl of brown rice with vegetables, meat and fish.
At 7pm, she has a protein shake. An hour later, she has fruit, such as a slice of watermelon, some grapes or half an orange.
At 9pm, she has a small bowl of wholegrain beehoon soup with vegetable and minced pork.
Since her diagnosis, she has steered clear of chocolates, cakes and pastries.
Over the past year, she has kept to an exercise regimen of a 30-minute brisk walk three to four times a week and a one-hour yoga lesson once a week.
She said: "I always wonder why people can gain weight just by eating a little bit more, but I can't."
What the experts say
Undiagnosed medical conditions such as depression, an overactive thyroid, poorly controlled diabetes, kidney or liver disease and cancer can lead to weight loss, said Dr Stanley Liew, a consultant endocrinologist at Raffles Hospital.
Severely underweight people may be more susceptible to infections and suffer from hair loss, anaemia, infertility and osteoporosis.
But most healthy people who are underweight or have difficulty gaining weight have a naturally high metabolic rate, said Dr Joan Khoo, an endocrinologist at Changi General Hospital (CGH). This means they use as many calories as they eat.
Being mildly underweight (having a BMI of between 16 and 18.5) may be due to genes or being physically active and not eating enough, she added.
She said: "Studies have even shown that fidgeting can burn up to 350 more calories a day."
Dr Liew said Madam Chua might have to accept her low weight but could boost it by eating food with a low glycaemic index (GI) whereby carbohydrates are broken down slowly by the body and cause blood glucose to rise slowly.
Even fruit should be chosen carefully, he said. Fruit with low GI values are usually slightly sour with soft skin such as strawberries, kiwi fruit and avocados.
Mr Derrick Ong, a dietitian at Camden Medical Centre, said Madam Chua was wise to choose whole grains, which has low GI values, for some of her meals. She could go even further by replacing her white rice porridge with brown rice, and fried noodles and beehoon with tang hoon (bean vermicelli) soup.
He said she was eating the correct proportion of carbohydrates, which should be about half a person's total calorie intake in a day. He estimated that she needs 1,400 calories a day and would need to consume 500 more calories to gain weight.
He felt she is eating adequate protein and carbohydrates, so the only way for her to bump up her calorie intake would be to eat more unsaturated fat. This can be from food such as nuts and oily fish such as salmon and sardine. They should replace the saturated fat derived from butter and fried noodles in her current diet, he added.
To avoid elevating blood glucose levels, she should not have a heavy meal so late at night, he said.
Agreeing, Ms Ong Li Jiuen, a senior dietitian at the dietetic and food services department at CGH, said the diet for a person with impaired glucose tolerance should be the same as that for a diabetic.
Madam Chua's diet should include food that is low in fat and salt but rich in nutrients and fibre.
Ms Ong said Madam Chua is doing the right thing by having small frequent meals and advised her to eat at around the same time each day to prevent fluctuations in blood glucose levels.
She advised Madam Chua to check the nutritional labels of the protein shakes for their carbohydrate and sugar content, which can affect blood glucose levels.
Ms Ong recommended that Madam Chua get a doctor's referral to consult a dietitian or exercise physiologist, who can provide her a safe and healthy weight-gain plan based on her nutritional needs.
Mr Ong also recommended that she do weight training or resistance exercise to build more muscle.
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