Hi, Marisol! Welcome!
We have loads of Europeans on the forums, including two Portuguese members. I'm Canadian, but can probably help. What you're looking for is an oil with very little taste. You still need to take it in a way that minimizes your sense of taste. Some throw it back like a shot while holding their breath, others float the oil on a small amount of water, possibly sweetened with a bit of plain sugar, and then drink quickly and rinse out the mouth to reduce residual flavour.
Bertolli makes an olive oil that is "mild" or "light", and that is a good one. Some folks use canola (rapeseed) or walnut oil, too. One of our European members has also used an inexpensive "salad oil", but I don't remember the name. The ones to avoid are the deep greenish, full flavoured olive oils, so the cheaper, more refined ones are better for this purpose.
Also, the 2 hour flavour-free window around your oil dose is vitally important to making this work. For an hour before and after the SLD calories, no other food or flavours, including gum or toothpaste. Your body absorbs the calories without any flavour messages going to the brain, and this is what seems to rewire the brain and allow for the setpoint to drop, causing the appetite suppression. It's really cool how it works.