One of the most emblematic buildings in the world is Sidney Opera House. You've definitely seen this spectacular building one of the most interesting features of which is its construction cost. When the construction of this emblematic building was agreed, engineers, field experts, people that have done this job all their lives, had estimated that the construction cost would be seven million dollars. When the project was completed, the cost had risen to 102 million dollars. The construction cost was 15 times higher than the original estimation. The cause of this was not that they wanted something modest at first, but then they said "We've got money, let's do something more impressive." It only had to do with a mechanism that we all carry in our minds, the planning fallacy. If you've ever had the unbearable experience to renovate an apartment, or even to build one, you've probably faced this problem many times. A crew had probably proposed a price that was very different than the final one. Or it was delivered much later that the deadline originally agreed upon. I guess this is no news to you. If you've ever needed to renovate or construct something, you must have noticed that the time and money you spent in the end were very different than what you had estimated in the beginning or even than what the contractor had told you. I guess many of you thought that the contractor asked for a smaller fee at first or promised to deliver sooner in order to get the job. Don't judge them so quickly. This is planning fallacy too. This fallacy haunts us all, both you and me. Every time my secretary gives me a list of five or six people to call in order to answer their questions, she always asks me "How long will this take you?" The answer is the one expected: "Ten minutes." This is never the case. It always takes me much longer. But we all tend to underestimate the problems that may arise and overestimate our abilities to complete something on time. We make a plan, but in reality, the journey is more complicated than we'd estimated. Problems arise that we could have imagined, but we had hoped they'd never happen. We're mentally prepared for the challenges, but we don't take them into account while planning. As a result, what we think will happen is very different than what actually happens. What does this have to do with diet? Every day, at the two medical nutrition centers that I lead, my team and I see dozens of patients that want a healthier diet. The first time we meet, we try again and again to stress the potential challenges. What will happen when someone has to eat at a restaurant? What will happen when someone brings sweets to your house? What will happen when your partner orders souvlaki and pizza for dinner again and again? The answers and solutions that we hear at our office are really simple. But reality is much harder. The secret for dealing with planning fallacy is not to ask what will happen when someone brings sweets to your house, but what happened the previous times when someone brought sweets. If the answer is that most of those times you ate a large amount of those sweets, consider this as the most probable outcome. Don't assume that this time will be different. Unless you can follow a different tactic. But is there any? Think about it. Thank you!