Leia o texto para responder à questão.
The secret of why we like to eat chocolate
Chocolate contains a number of interesting psychoactive chemicals. These include anandamide, whose name comes from the Sanskrit – “ananda”, meaning “joy, bliss, delight”. Anandamides, a neurotransmitter, stimulate the brain in much the same way that cannabis does. It also contains tyramine and phenylethylamine, both of which have similar effects to amphetamines. Finally, if you look hard enough, you will find small traces of theobromine and caffeine, both of which are well-known stimulants.
For a while, some food scientists got very excited about the discovery but, although chocolate contains these substances, we now know they are only there in trace amounts. Your brain is not going to get much of a chemical rush from eating a few squares. None the less, they may play a small part in seducing our senses. So what else does chocolate have going for it? Well, it also has a creamy viscosity. When you take it out of its wrapper and put a bit in your mouth without biting, you will notice that it rapidly melts on your tongue, leaving a lingering sensation of smoothness. Special touch receptors on our tongues detect this textural change, which then stimulates feelings of pleasure.
But the thing that really transformed the cocoa from a bitter and watery drink into the snack we adore today was the addition of sugar and fat. The addition of just the right amount of each is crucial to our enjoyment of chocolate. Look at the side of a packet of milk chocolate and you will see that it normally contains around 20-25% fat and 40-50% sugar. In nature such high levels of sugar and fat are rarely found, or at least not together. You can get lots of natural sugars from fruits and roots, and there is plenty of fat to be found in nuts or a tasty chunk of salmon, but one of the few places where you will find both together is in milk.
Human breast milk is particularly rich in natural sugars, mainly lactose. Roughly 4% of human breast milk is fat, while about 8% is made up of sugars. Formula milk, which is fed to babies, contains a similar ratio of fats to sugars. This ratio, 1 g of fat to 2 g of sugars, is the same ratio of fats to sugars that you find in milk chocolate. And in biscuits, doughnuts, ice cream. In fact this particular ratio is reflected in many of the foods that we find hard to resist. So why do we love chocolate? For a whole host of reasons. But it may also be that we are trying to recapture the taste and sense of closeness we got from the first food we ever sampled: human breast milk.
(Michael Mosley. www.bbc.com, 24.02.2017. Adaptado.)
In the excerpt from the fourth paragraph “Roughly 4% of human breast milk is fat”, the underlined word can be replaced, without changing the meaning of the sentence, by
