Can you remember what you ate yesterday? If asked, most people will be able to give a vague description of their main meals: breakfast, lunch, dinner. But can you be sure you’ve noted every snack bar in your car, or every handful of nuts at your desk? 【小题1】

We originally had this suspicion back in 2016, puzzled by the fact that national statistics showed calorie consumption falling dramatically over past decades. Now, the Office for National Statistics has confirmed that people are considerably under-reporting what they ate by 50%.

【小题2】 We can point to at least three potential causes. One is the rise in obesity levels itself. Under-reporting rates are much higher for obese people, because they simply consume more food, and thus have more to remember.

Another cause is that the proportion of people who are trying to slim down has been increasing over time. 【小题3】 It may be driven partly by self-deception or “wishful thinking”.

【小题4】 Both are in terms of how often they happen and how much they contribute to our overall energy intake. Again, there is evidence that food consumed out of the home is one of the most poorly recorded categories in surveys.

So, what’s the message conveyed? If people do not know how much they are eating, it can be really hard for them to stick to a diet. 【小题5】 Therefore, we can ensure what people eat won’t have much impact on their waistlines. If this works, it won’t matter if they can’t remember what they ate yesterday.