After all, they have a lower GI than pound cakes, sodas and even – watermelons. But consider that a watermelon is lower in calories and has more essential nutrients than a candy bar, and the whole GI thing sounds a little dodgy.

So what is GI? Well, it is an index that ranks foods based on the impact they have on our blood sugar.

“When the GI of a food is high, the glucose very quickly travels into the blood, which then needs to be quickly quelled by insulin – our blood sugar regulator,” says Sheeba Majmudar, Men’s Health Ask the Nutritionist columnist.

High glycaemic foods cause blood sugar to rocket, then come crashing down, which triggers the appetite and causes one to crave more food (and carbs). There would therefore be a tendency to overeat.

Also, high blood sugar triggers the release of excessively high levels of insulin, which may signal your body to store the sugar as fat. This is especially so if your muscle cells are not starved of energy.

It is usually better to ensure balanced blood sugar levels – and in turn, balanced insulin levels. This helps to maintain a steady stream of sugar to our muscle cells and reduces the likelihood that our body will store fat.

The problem with GI though, is that it does not take into account real-world portion sizes. The GI of a food is derived from an amount of the food that gives 50g of digestible carbs (this includes starch and sugar but not fibre).

For candy, this works out to just three-quarters of a king-size bar. But one would have to eat five cups of diced watermelon to get the same amount of carbs.

It is thus flawed to compare these two foods as such.

Also, GI is not a fixed number. It can vary by as much as 54 per cent from person to person, according to a study by University of Toronto (Canada) scientists. It can also vary within the same person – the effect of a high-sugar drink on blood glucose drops by 12 per cent for 12 hours after an intense workout.

And consider that we seldom eat foods in isolation – adding fat or fibre to a meal slows the absorbtion of glucose in the bloodstream. This further affects the usefulness of the GI.

For people watching their weight, the total calories consumed is the most important factor in managing one’s weight. Going back to the candy – watermelon example, it is clear that low GI does not necessarily mean low-carb.

Faux Flesh
Those dishes of vegetarian meat can masquerade as the real deal convincingly well, but they can be “shockingly high in fats and sodium”, says Majmudar. Just compare an equal portion of vegetarian roast duck to real duck – according to the Health Promotion Board, the former contains up to 100 more calories, 12g more fat and 555mg more sodium! “There is very little nutritional value in mock meat because they’re so highly processed,” she says. Even though mock meats are made of gluten and soy protein, they’re put through such high temperatures and pressures to bring about a meaty texture that most health benefits of the original ingredients are lost. A simple rule of thumb Majmudar offers: Avoid foods that cannot be identified from their natural state – the simplest rule of good health.

Veggie Good
Go for steamed varieties of foods when you’re dining at a vegetarian restaurant (even boiling leaches vitamins from vegetables). “Because direct heat is not used on the vegetables, more vitamins are preserved,” says Majmudar. Get a variety of foods like tofu, mushrooms, lentils, beans (for protein) and unrefined grains like brown rice for the best nutritional kick, she says. Also if you’re looking to ditch meat and head down the vegetarian road, it’s advisable to consume more B complex vitamins that are less prevalent in such a diet. Eat more mushrooms, miso, azuki, wholegrains and supplement with a multi-vitamin for additional nutritional support, she advises.

Nutritional Punch
Ever wonder if agar-agar has any health benefits at all? This gummy dessert may appear to tread in a nutritional no-man’s land, but it’s surprisingly not that bad a dish to consume. “Sea vegetables and algae can be an excellent source of nutrients such as protein and fibre,” says Majmudar. Also, agar-agar is made up of polysaccharides that are, in essence, complex carbohydrates – such carbs are broken down into glucose more slowly by the body, resulting in a constant release of energy. This also allows you to feel fuller for longer. Though certain agar-agar sources may be low in fibre, the right kinds can be “a good source of fibre without significantly increasing caloric intake… great for individuals who don’t meet the daily recommendation of 25-30g of fibre per day,” says Wong.

Diet Down
If you’re clued in to Japanese trends, you’ll have heard of the “kanten diet”, or rather, a diet in which you eat agar-agar before each meal. The result: You could consume less food overall credit to the gelatinous substance’s ability to absorb water and its fibre content, says Majmudar. “Agar-agar contains proteins, polysaccharides, minerals and vitamins and can be incorporated into any food plan,” she says. But as with the kanten diet, she recommends having it before a meal rather than as a dessert to experience the biggest weight-loss benefits. Still, Wong points out that any fibre source (fruits and vegetables included) will have a similar appetite-curbing effect. Adding fruits is the best way to bump up agar-agar’s nutritional content, says Majmudar. “You don’t even need to add sugar. It’s a nutritionally complete food in itself.”