Ever had a negative-calorie meal? This is how ‘zero-calorie’ foods measure up

SINGAPORE: How much more would you pay for sugar substitutes with no calories?

For events operations co-ordinator Janice Neo, her spending on these products comes to “quite a bit”. “Two kilogrammes of sugar will probably cost you S$5, but I’m willing to spend up to S$50 on the monk fruit sweeteners,” she said.

She is not alone in that. Spark Chen, a tertiary student on a weight-loss journey, spends “30 to 40 per cent” of his monthly food budget on zero-calorie products.

But do these foods and drinks live up to their name and contain no calories at all?

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The programme Talking Point put some of the more popular products to the test — zero-calorie sriracha, konjac jelly, olive oil cooking spray, zero-calorie isotonic and carbonated drinks and a honey substitute — and the results surprised some users.

WATCH: Zero-calorie food — What am I eating? Is it healthier? (22:10)

Of the six foodstuffs sent to testing, inspection and certification company SGS Singapore, only one had truly no calories. The other five contained two to six calories per serving.

According to Health Promotion Board (HPB) guidelines, products with up to five calories per serving can be packaged for sale as calorie-free.

Responding to Talking Point’s queries about the product found to have six calories per serving — the konjac jelly — the Singapore Food Agency (SFA) and the Health Promotion Board said there is “an allowance of 20 per cent variance during lab testing”.

Still, the SFA is “looking into the matter”.

Products like the olive oil spray, however, can be labelled “zero-calorie” despite containing two calories per serving and the whole bottle containing 1,074 calories.

A serving here, as defined on its Nutrition Information Panel, is a third of one second of spray. This means a “zero-calorie” count results only when consumers use the recommended portion control.

“People are just going to pick up (this product), saying: ‘This is zero calories — let me just use this,’” said Carolyn Stephen, lead nutritionist at the Singapore Polytechnic’s Food Innovation and Resource Centre.

The one product that was tested and really had zero calories was the honey substitute, made with monk fruit syrup. Many zero-calorie products, however, contain artificial sweeteners, which evidence suggests is not as good for you as you might think.

SUGAR-FREE SWEETNESS EXPLAINED

So how is a product like zero-calorie “honey” made? The key ingredient is monk fruit, “more commonly known in Singapore as luo han guo”, said Dominic Li, director of local company Zest Foods, which distributes the product.

“It’s a citrus fruit … that (has) an extract called mogrosides, which is a sugar compound … that’s similar to honey without having any of the calories,” he said.

“(The extraction process) involves the monk fruit being boiled, and then there’s a few steps of dehydration and drying until it becomes a powder. … After that, it’s caramelised.”

These sweeteners are known as intensive sweeteners, since they provide “100 or 200 times” more sweetness intensity than sugar, said Stephen. “So you … use very, very little, as compared to table sugar.

“(Along with) the fact that your body doesn’t metabolise it — you taste it, but you don’t absorb it, you don’t get energy out of it — that’s why they’re calorie-free.”

CALORIC DEFICIT FROM EATING?

With ingredients containing virtually no calories, is it then possible to eat a negative-calorie meal? The concept is increasingly popular among people who are trying, for example, to adopt a healthy lifestyle or lose weight, observed consultant gastroenterologist Andrea Rajnakova.

They believe that certain foods require more energy to digest than the caloric content of the food itself, she said and cited celery, lettuce, tomato and watermelon as examples.

But there are some misconceptions about this weight-loss method, cautioned Rajnakova, who detailed how the energy required to metabolise food — the “thermic effect” of food — accounts for a very small portion of the body’s energy expenditure.

“If we’re (taking) these sorts of foods as a part of our diet, the contribution of the thermic effect of the meals is so negligible that we won’t be able to expect any weight changes,” she said.

So, as food substitutes, zero- or low-calorie products might reduce calorie intake but on their own will not be enough to push the body into a negative-calorie state.

A HEALTHIER CHOICE?

Opting for sugar substitutes may not be the best idea either. Rajnakova cited recent studies on some digestive side effects of artificial sweeteners, such as bloating, flatulence, and loose stools.

“(This is) because (the sweeteners) aren’t absorbed by our digestive system,” she said.

She also mentioned recent studies showing that some artificial sweeteners may increase blood clotting and the risk of cardiovascular disease.

And despite the natural, plant-based origins of sweeteners such as stevia and monk fruit, she said these zero-calorie options fall into the category of “artificial sweeteners with the possibility of side effects” on the digestive system.

“If they give you zero calories, the value of the nutrient is also zero,” she added.

CONSUMERS REACT

But even if the calorie count is not really zero — a tablespoon of zero-calorie sriracha sauce is 12 calories, compared to four calories in a teaspoon — some users think these products are worth the price.

In the case of the monk fruit honey, the price difference is close to three times, but it remains one of Neo’s favourite products. “It still makes a big (caloric) difference compared to the real version,” she said.

“It’s still going to be the healthier alternative,” said Hakim Rahim, a senior designer who consumes zero-calorie products on an almost daily basis.

For fitness coach Leon Tan, however, the number of calories in the plant-based konjac jelly came as a surprise. “Six calories is probably on the high side,” he said.

“If some of my trainees or my followers ask me whether this is a great zero-calorie product, I’ll probably tell them that this has a little bit more calories, so just be mindful of how many you eat.”

Watch this episode of Talking Point here.