Fast track to good health

Fasting shows more promise for obese people than healthy adults

The Straits Times (13 June 2017) - It is Ramadan, a month when Muslims around the world fast during daylight hours. They are not the only group who practise fasting, as practitioners of other religions also fast from time to time.

Intermittent fasting – taking breaks from eating – is also increasingly practised for health reasons.

Fasting patterns vary. For instance, it can mean eating less on two days a week or every other day.


About 4,000 residents breaking fast together at a special
event at Marsiling Mega Sports Park on June 4.
PHOTO: LIANHE ZAOBAO Fast track to good health


Some people opt for intermittent fasting to lose weight. When we eat, the body stores sugar as glycogen.

A body that is deprived of food will start to use its glycogen stores.

Once these stores are used up, the body burns fat for energy, resulting in weight loss, said Ms Bibi Chia, the principal dietitian at Raffles Diabetes & Endocrine Centre.

Indeed, intermittent fasting that involves eating less on alternate days or two days a week has been shown to lead to weight loss in overweight people, said Dr Abdul Shakoor S.K., a senior consultant at Tan Tock Seng Hospital’s department of endocrinology.

But while fasting has definite benefits for people who are obese, there is no definitive proof of its benefits for healthy people, he said. Intermittent fasting may also lower the risk of metabolic and cardiovacular diseases in obese and non-obese people, he said.

However, there is insufficient evidence to show that it is a way for diabetic patients to control blood glucose levels, he added.

Besides, most people find it hard to restrict their calorie intake over the long term. It is also natural to overeat during non-fasting hours, which negates any weight loss.

Dr Quah Boon Leong, a staff physician in general surgery at Khoo Teck Puat Hospital, said: “According to one study, weight changes during Ramadan were relatively small and mostly reversed after that, gradually returning to pre- Ramadan status. Consistent lifestyle modifications are necessary to achieve lasting weight loss.”


Intermittent fasting is not just about weight loss. “Some studies indicate a decreased risk of coronary heart disease and diabetes among those who fast routinely,” said Dr Sueziani Zainudin, a consultant endocrinologist at Sengkang Health’s general medicine department. “Studies also report behavioural changes, including improvement in mood, increased alertness and mental acuity, and tranquillity.”

Dr Abdul Shakoor said alternateday fasts in animals have been shown to lead to longer lifespans. It has also been shown to prevent or delay heart disease, diabetes, cancer, neurological disorders and stroke.

“However, there is no convincing evidence from human studies to show that fasting or caloric restriction help to ward off or delay the onset of chronic diseases,” he said.

Therefore, while healthy adults may fast for religious reasons, they do not need to fast specifically for health purposes as there is insufficient evidence to show that intermittent fasting will prevent certain diseases or prolong life in humans, he said.


Doctors said fasting is not suitable for people who are ill, elderly, pre-pubescent or have eating disorders, as well as women who are pregnant or breastfeeding.

It may affect diabetic patients on medication or those with heart, kidney and liver conditions who take medications that induce water loss, said Dr Sueziani.

Dr Quah said the health risks of fasting during Ramadan are hypoglycaemia (low blood glucose levels) and dehydration. “Severe hypoglycaemia could lead to convulsions and falls, and may be fatal.”

While intermittent fasting shows promise, a lot of questions remain unanswered. Ms Chia said these include which is the most effective fasting pattern, the optimal calorie consumption during the fasting period and how sustainable it is in the long term.

Dr Abdul Shakoor said if intermittent fasting with low-calorie diets is practised frequently, it may affect one’s ability to get adequate essential nutrients.

Most international dietetic associations do not recommend following a very low-calorie diet for more than 12 weeks, he said.

When fasting, look out for signs like dehydration, heartburn, bad breath, headaches, increased irritability and dizziness, said Ms Chia.

“Stop when there are signs of shivering, extreme thirst, heart palpitation or extreme weakness.”

Mistakes that diabetics make when fasting

Diabetic patients may think that fasting during Ramadan will help to improve their blood sugar control since they are eating less.

However, there are risks associated with fasting for diabetics.

Dr Ester Yeoh, a consultant at Khoo Teck Puat Hospital’s Diabetes Centre, said the risks of fasting during Ramadan include low blood glucose (hypoglycaemia), high blood glucose (hyperglycaemia), dehydration and emergencies like diabetic ketoacidosis.

During fasting, some types of anti-diabetic medication can increase the risk of hypoglycaemia in the elderly and in patients with kidney impairment or failure, she said.

Patients can take precautions by monitoring their glucose levels and adjusting their medications.

Under Islamic law, people with diabetes do not have to fast during Ramadan. Those who want to fast should heed their doctor’s advice to prevent any complications, said Ms Melissa Ho, senior dietitian at Tan Tock Seng Hospital.

Here are some mistakes diabetics may make when fasting:

  1. Not monitoring blood sugar
    Pricking the skin to test for blood sugar levels does not invalidate the Ramadan fast, said Ms Ho. Check your blood sugar levels regularly to monitor how the change in eating habits impacts blood sugar levels during fasting.
  2. Delaying treatment
    Do not delay the treatment of low blood sugar levels to avoid breaking fast, said Ms Ho.
    “Delaying treatment can lead to fainting, diabetic coma and brain damage,” she said. “If low-sugar events are not promptly treated, patients will gradually not be able to feel the warning symptoms.”
    She said patients should check their sugar levels frequently, especially if they notice symptoms of low sugar levels or hypoglycaemia, such as breaking out in cold sweat, weakness, fatigue, trembling, dizziness, confusion and headache. If their blood sugar level is below 4mmol/L, they should break the fast and take 15g of sugar. This can be three non-sugar-free sweets, half a glass of juice or soft drink, or three teaspoons of sugar dissolved in water. Wait for 15 minutes and check the blood sugar level again. If it is above 4mmol/L, take a snack containing carbohydrates or have a meal earlier.
    If the reading is below 4mmol/L, take another 15g of sugar and repeat till the blood sugar level is back to normal (above 4mmol/L).
  3. Not preparing ahead Diabetes medications should be adjusted by the doctor before the fasting period to prevent poorly controlled blood sugars, said Ms Ho. Do not start fasting and wait for complications to arise before finding out if the medications should be adjusted.
  4. Over-indulging in food
    Maintaining a healthy and balanced diet is important during Ramadan. Avoid taking large, carbohydrateheavy meals and sugary drinks after breaking fast as this can increase the risk of complications in people with diabetes, said Dr Yeoh. Consume foods with low glycaemic index and high fibre as these release energy slowly, and eat less of foods that are high in saturated fats. Be aware of the risk of hyperglycaemia and avoid overindulging in food and sweet drinks. After the festival, diabetics should revert to their usual antidiabetic therapies and continue to check blood glucose levels, said Dr Yeoh.



Under Islamic law, people with diabetes do not have to fast during Ramadan. ST PHOTO: JAMIE KOH 

Getting children to fast during Ramadan

Fasting during Ramadan is for those who have attained puberty.

Islam does not require young children to fast, although many parents train them gradually over the years to enable them to fulfil this obligation by puberty, said Dr Sueziani Zainudin, a consultant endocrinologist at Sengkang Health’s department of general medicine.

Parents will need to tailor the training to suit the child, as it depends on the child’s readiness, maturity level, tolerance and ability to express his needs, she said. “Ideally, fasting should be performed under adult supervision.

Parents should ensure that the child is not unwell and does not engage in high-intensity physical activity, which could make fasting risky.”

Such training should be done gradually, she said.

Studies have suggested that fasting affects a person’s performance because it disturbs sleep patterns, food and fluid intake, as well as circadian rhythms, she said. Thus, parents should ensure that the child remains active and alert while fasting.

If the child shows signs of dehydration, such as lethargy, dry mouth and decreased urine output, fasting should be terminated.

The child will need to be fed and, if necessary, receive medical attention, she said.

Parents whose child has health conditions but who wishes to fast should discuss it with a paediatrician, she added.

Before you go on a fast

More studies are suggesting that intermittent fasting may have health benefits such as weight loss, lowering of blood pressure, reduced blood cholesterol and blood glucose improvement, said Ms Gladys Wong, chief dietitian at Khoo Teck Puat Hospital.

Although there is insufficient evidence to suggest that fasting is necessary for disease management, some people may still want to do it for health reasons.

For people who do not have any pre-existing health conditions, she said, there is no harm in engaging in some sort of fast.

If fasting can help one to become more mindful of one’s food intake, she added, it can be used as a strategy for weight control.

However, she said there are two things to take note of:

    If you are fasting for more than 12 hours, your weight may drop but that is mainly water weight. You need to monitor this to ensure you do not become dehydrated.
    Do not exert your body too much if you are on a fast, unless you are very confident it can function without food and water.

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