This story was first published in November, 2015 in an e-book titled 50 Food Myths Busted, in The Straits Times Star E-books app. In the book, experts clear the air on widely held misconceptions and beliefs about food. They address questions on myths on the daily diet, pregnancy and babies, fuelling workouts, sickness and what we drink. The book was conceptualised and written by the team at Mind & Body, the weekly health features section in The Straits Times.
PREFACE BY POON CHIAN HUI, EDITOR, MIND & BODY
Eat this, not that. People have plenty of beliefs about food – even more so when it comes to their health.
At Mind & Body, a health features section of The Straits Times, we get questions from readers about nutrition, dietary guidelines and even warnings about certain food items.
But the answers aren’t always clear-cut. Studies may contradict each other, and experts can have different opinions.
The Mind & Body team rounded up 50 confounding food myths and asked doctors and dietitians islandwide to clear the air, once and for all.
You will also find handy tips on how best to navigate each situation.
Should you always choose fresh produce over frozen food? Does eating before exercise give you cramps or stitches? And will consuming more fibre help to ease constipation?
Read on to find out – the answers may surprise you.
CHAPTER I. THE DAILY DIET
MYTH 1: REPLACE WHITE SUGAR WITH BROWN SUGAR, HONEY OR AGAVE SYRUP FOR A HEALTHIER FIX
These sugars are no better than refined white sugar, which is a simple carbohydrate that is easily utilised by the body for energy but stored as fat if it is not needed.
“Essentially, all sugars are the same, with minor differences in terms of the presence of minerals, impurities and colouring,” said Ms Jenny Ng, principal dietitian at Mind Your Diet.
“Regardless of the type of sugar, it will eventually be broken down into glucose, which will enter our bloodstream and be used as energy by our cells.”
Sugar should be taken in small amounts as it provides empty calories and has no nutrients.
Ms Ng said people should watch out for hidden sugars in food and drinks. Soft drinks, in particular, have a lot of sugar - one can of drink can have as much as eight teaspoons of sugar, she said. And if you add sugar to your drinks or to your food while cooking, you may be increasing your caloric intake significantly without realising it.
MYTH 2: A CALORIE IS A CALORIE, SO IT DOESN’T MATTER WHAT TIME OF THE DAY YOU EAT, INCLUDING LATE-NIGHT MEALS
It does, said Ms Sarah Sinaram, senior dietitian at Raffles Diabetes & Endocrine Centre.
An Australian study published in 2007 showed that night eating syndrome, where most food is consumed in the evening and night, was associated with a higher body mass index, she said.
Another study done in 2013 concluded that eating more of the day’s total energy intake at midday is associated with a lower risk of being overweight or obese, while consuming more in the evening is associated with a higher risk.
When it comes to eating late at night and its potential for weight gain, the following points should be considered, she said.
1. Portion sizes: Delaying your mealtimes can lead to consumption of larger portion sizes.
2. Quality of food: After a long day at work or school, fast food may seem more appetising than steamed vegetables and broiled fish.
3. Mindless snacking: Snacking on fried, oily or sugary snacks while studying or watching TV may result in the consumption of excess calories.
4. Health concerns: Going consistently without food for long periods of time, only to follow it with a large meal, can negatively impact the interaction between your blood sugar and insulin and make yourself more vulnerable to type 2 diabetes.
Limiting late-night meals and snacks may be an effective weight management strategy for some people because it helps them to control their overall calorie intake.
Some people find it helpful to set a time limit each day to make sure they do not eat past a certain time. This helps them to minimise or eliminate the possibility of munching on a lot of high-calorie food at night.
MYTH 3: RADIATION FROM MICROWAVE OVENS KILLS MORE NUTRIENTS IN FOOD COMPARED TO CONVENTIONAL COOKING.
Not true, at least, that is what current evidence shows. If properly used, cooking using microwave ovens do not affect the nutritional content of food more than conventional heating on the stove.
Rather, as the microwaves affect mainly water molecules, they “steam” food from inside out, and this helps to retain most nutrients, according to an article in Harvard Health Publications by Harvard Medical School in the United States.
It is important to note that all types of cooking tend to cause a loss of nutrients, according to dietitians and food scientists. The key to minimising it is to keep the cooking time short with the least possible amount of liquid – something that microwave ovens fare well at.
Try not to cook vegetables in water using the microwave, unless you intend to consume the water as well. This is because nutrients may leach out into the water, according to Harvard Health Publications.
You can try steaming greens in the microwave instead, by placing a container of water inside the oven.
MYTH 4: CHOOSE MARGARINE OVER BUTTER TO LOWER YOUR RISK OF HEART DISEASE
It’s not that simple.
Indeed, margarine products that are based on plant oil are mostly higher in unsaturated fat, which is known to be beneficial for our heart health. They also contain lower amounts of unhealthy saturated fat, said Ms Gina Lin, a dietitian at Singapore General Hospital.
The only exceptions, however, are those made of palm oil. Up to 50 per cent of its content can be saturated fat, she pointed out.
Also, the hydrogenation process of making margarine from plant oil high in unsaturated fats can create trans fat. This type of fat increases one’s risk of heart disease as it raises the level of “bad” cholesterol and lowers the level of “good” cholesterol in the body.
The softer the margarine, the lower its trans fat content. So, soft or tub margarine made from plant oil high in unsaturated fat (such as olive, sunflower and canola oil) is better. Choose those labelled with the “trans-fat free” Healthier Choice Symbol, as this indicates that they contain no more than 0.5g of trans fat per 100g of margarine. You can also choose margarine labelled as “reduced fat” or “reduced salt to further decrease your risk of developing heart disease.
MYTH 5: FROZEN YOGURT IS BETTER FOR YOUR HEALTH THAN ICE CREAM
Frozen yogurt and ice cream are both made from dairy sources, yet frozen yogurt has been dubbed a healthier alternative to ice cream.
Indeed, yogurt is lower in fat due to the use of milk instead of cream.
But fat-free or low-fat products may not be low in calories and sugar.
Sugar makes up 15 to 20 per cent of the ingredients in frozen yogurt, which is equivalent to the sugar content in ice cream, said Ms Janie Chua, a senior dietitian at National Healthcare Group Polyclinics.
A serving, or about 90g of ice cream, provides 180kcal; 100g of frozen yogurt provides 150kcal.
A better alternative to frozen yogurt would be natural low-fat yogurt, which is lower in calories and sugar, she advised.
A serving of natural low-fat yogurt, or about 120g, has 100kcal.
Based on a 100g serving, the sugar content of ice-cream, frozen yogurt and natural low-fat yogurt would be 23g, 24g and 14g respectively.
In addition, frozen yogurt may have less probiotics than yoghurt as some live cultures may be killed during its freezing process.
If you are watching your fat and calorie intake, you may opt for frozen yogurt, but it is important to moderate your portion size and avoid toppings that are high in fat and sugar, such as assorted flavoured syrups, chocolate chips and marshmallows, said Ms Chua. Instead, go for toppings such as fresh fruits or nuts, which are lower in calories, fat and sugar.
MYTH 6: FRESH PRODUCE IS MORE NUTRITIOUS THAN FROZEN OR CANNED FOOD
Not always. Fresh fruit and vegetables, if not stored properly, may lose their nutrients fairly quickly.
But if frozen quickly after harvest and stored properly, a significant amount of their nutrients can be retained for up to a year, said nutritionist Benjamin Lee and dietitian Chelsea Chang from Health Promotion Board (HPB).
Phytochemicals, antioxidants that are found in fruit and vegetables, can sometimes be more abundant in processed food. Heat applied during the canning process, for instance, can increase the levels of lycopene, which is associated with a reduced risk of prostate cancer, they said.
In general, you won’t find any less phytochemicals in frozen and canned food, compared to fresh ones.
Frozen or canned products can be a good way to stock up on fruit and vegetables at home to meet your daily recommended intake (two servings of each), especially if you are too busy to buy fresh varieties regularly, said Mr Lee and Ms Chang.
Do note, however, that canned food usually contain lower amounts of heat-sensitive nutrients, such as vitamin C. Canned fruit also tend to contain sugar syrup, while canned vegetables are preserved with brine. Therefore, look for items that are lower in salt or contains light syrup or natural juice.
MYTH 7: REGULAR REFINED SALT IS LESS HEALTHY THAN SEA SALT, OTHER FANCY SALT OR SALT FLAKES
All salt comes from either the sea or salt deposits, and they all contains sodium, which can raise one’s blood pressure if consumed in excess.
“Sea salt and table salt are basically the same in terms of nutritional value. By weight, they contain the same amount of sodium,” said Ms Chloe Ong, a dietitian with CanHOPE Counselling & Support Services at Parkway Cancer Centre.
The difference between sea salt and table salt lies in how they are produced and their texture.
Sea salt is usually produced through the evaporation of sea water.
Depending on the water source, some trace minerals and elements, such as magnesium, may be left behind, said Ms Ong.
While table salt, sea salt or kosher salt are not much different in sodium content by weight, there is a difference by volume, as sea salt and kosher salt are usually coarser than table salt.
This means that if you keep to a recipe that calls for a teaspoon of salt, for instance, you will consume less sodium if you use the larger-grain kosher salt instead of fine-grain table salt.
MYTH 8: SKIPPING MEALS WILL HELP YOU LOSE WEIGHT
When we skip a meal, we tend to inadvertently overeat at the next meal. We will also crave snacks, said Ms Ler Yi Bin from Mount Alvernia Hospital’s nutrition & dietetics services.
So, in the long run, skipping meals can lead to weight gain.
In fact, during a “fasting state”, the body will push to conserve calories rather than burn them, she added. It first breaks down glycogen, which are energy stores, in the muscles and liver, before using fat for energy. The amount of energy output reduces, and lean tissue begins to shrink and grow weaker. Meanwhile, hormones will also slow down your body’s metabolism.
Try not to skip any meals, especially breakfast. Our body’s metabolism slows down during sleep, and delaying a meal will result in a tough time digesting the food later, said Ms Ler. A big meal after a long delay may even lead to weight gain as more calories get stored as fat. Also, don’t just drink coffee for breakfast. Fluids get digested faster than solid food, so hunger pangs may strike earlier and you may end up eating too much at lunchtime.
MYTH 9: SPLITTING CALORIES BETWEEN SIX MEALS, COMPARED TO THREE SQUARE MEALS A DAY, STAVES OFF HUNGER AND BOOSTS WEIGHT LOSS EFFORTS
When it comes to losing weight, it does not matter if you have six small meals or the usual three meals a day.
“It is really up to the individual to decide how many meals he or she is able to have in a day,” said Ms Sarah Sinaram, a senior dietitian at Raffles Diabetes & Endocrine Centre.
For example, a salesman may only be able to have three meals a day due to his schedule while an office worker can choose to have up to six meals per day, she said.
Ultimately, it’s the calories consumed that matters. “If both are consuming fewer calories than their caloric output, both will lose weight,” said Miss Sinaram.
Reduce your overall calorie intake if you want to lose weight. If you eat more calories than what your body uses for daily activities and exercise, you will gain weight.
“Research tells us that following any diet that advises calorie restrictions can result in weight loss,” said Ms Sinaram.
MYTH 10: REMOVE THE SKIN ON FOODS, LIKE POTATOES AND APPLES, AS THEY CARRY GERMS AND ARE LOW IN NUTRIENTS
Many people tend to remove edible skins from their food, such as apples and potatoes, but they contain beneficial vitamins, minerals, phytochemicals and fibre, said Ms Ler Yi Bin from Mount Alvernia Hospital’s nutrition & dietetics services.
If you were to compare the flesh or pulp of the food and its skin, the skin is packed with more fibre. In addition, it usually contains insoluble fibre, which adds bulk to stools and prevent constipation, said Ms Ler.
The peel of some types of citrus fruit, such as oranges, lemons and grapefruit, also contains vitamin C, which aids in immunity.
And fruit peels of berries, guava and grapes carry higher levels of antioxidants than their flesh.
Eat edible skin whenever you can. Just make sure to wash them thoroughly to remove any dirt and soil, said Ms Ler.
CHAPTER II: PREGNANCY AND BABIES
MYTH 11: PREGNANT WOMEN SHOULD EAT FOR TWO
A pregnant woman should not double her normal food intake, said Dr Ann Tan, an obstetrician and gynaecologist at the Women & Fetal Centre at Paragon.
If she eats too much, she will end up putting on too much weight. This can increase her risk of gestational diabetes, backaches and high blood pressure. She may even need a caesarean birth because her baby is too big.
In the first six months of pregnancy, a woman will need an extra snack a day, containing 200 to 300 calories, said Dr Tan. This is the equivalent of a bowl of cereal with low-fat milk and a small banana, a bowl of soup or a muffin, she said.
And in the last three months of pregnancy, she will need up to 500 calories more than her normal intake per day as there is much more weight gain and growth of the baby at this stage, said Dr Tan. This can be a sandwich or a low-fat meal, she said. For those who start off being underweight or overweight, their calorie needs will be different.
For mothers carrying twins, their calorie requirements will have to be increased accordingly, said Dr Tan.
MYTH 12: EATING FOOD THAT CONTAINS OESTROGEN BOOSTS FERTILITY
Too much of this female hormone will upset the normal hormonal balance in the body, and this is actually detrimental to one’s fertility, said Dr Loh Seong Feei, medical director at Thomson Fertility Centre.
In fact, the effects of oestrogen-containing food is a complex matter, he added.
It depends on your body status and whether you have any medical conditions which may be worsened by the presence of oestrogen, such as endometriosis, where the lining of the uterus grows outside the womb, he said.
Men can get a fertility boost from eating foods that are high in antioxidants, as these are beneficial to the production of healthy sperm, said Dr Loh.
MYTH 13: CAFFEINE, LIKE SMOKING, LOWERS YOUR CHANCES OF GETTING PREGNANT
There is conflicting evidence on this, said Dr Loh Seong Feei, medical director of Thomson Fertility Centre.
A multi-centre European study published in 1997 found that women who consumed 500mg of caffeine or more daily took a longer time to get pregnant. The authors concluded that high levels of caffeine might delay conception, said Dr Loh.
But a review of studies from 2000 to 2009 found that caffeine consumption did not seem to affect fertility, sperm quality and success rates of in-vitro fertilisation (IVF).
What is very clear, though, is that smoking lowers your chances of getting pregnant.
“Smoking has consistently been proven to affect various aspects of human fertility, including egg reserves, sperm quality and IVF pregnancy rates,” said Dr Loh.
In the light of the initial 1997 study, doctors still generally advise women who want to get pregnant to reduce their consumption of coffee to one or two cups a day, said Dr Loh.
Source: The Straits Times © Singapore Press Holdings Limited. Reproduced with permission.
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