It is not uncommon for me to hear patients describe how they can go the whole day without eating due to being busy with work schedules and other tasks, but then as soon as they get home they realise how hungry they actually are. This often leads to highhurdling the kitchen bench to get to the fridge and spending the next 20 minutes eating a large amount of food as quickly as possible in order to raise their blood sugar levels again. This feeding frenzy is usually followed by skipping dinner, the very meal that has the most vegetable intake for most people, and so these individuals, night after night, are missing out on eating the recommended serves of vegetables. Sooner or later they find they are carrying too much weight around their middles and not really realising that it has to do with this after-work eating pattern.
See, when our blood sugar falls below a certain level the hunger centre in a part of our brain called the hypothalamus is activated, which compels us to eat. The main foods you will naturally desire will be carbohydrates and sugars to raise blood sugar the fastest. The hungrier you are the more your body will crave carbohydrates and sugars as a way of restoring blood sugar levels quickly. These foods also raise serotonin, which is a neurotransmitter associated with feelings of fullness and well-being. When we eat foods that raise the blood sugar our hunger centre is then switched off. Our hunger centre can also be switched off by hormones that are released by the stretching of our stomach and by the presence of fats and proteins in our meal.
It is important to not skip meals as you will end up being too hungry and this can lead to an overwhelming desire to binge on the less healthy food options. Such foods are often addictive in their very nature and therefore all tend to lack the proper ratio of carbohydrates, proteins, fats and fibre to ensure that the hunger centre is turned off for many hours. Instead, these foods are rapidly absorbed and both spike blood sugar and insulin levels – leading to a to cycle of consumption and craving for the wrong types of foods. Over time, it becomes harder to break this cycle as insulin levels become chronically elevated, causing fluctuations in blood sugar. And if the cycle continues, it is possible to become insulin resistant so that adequate blood sugar is never able to enter the cells – including those in the hypothalamus – and turn off the hunger centre in the brain. The result is a ravenous appetite and eventually pre-diabetes or type 2 diabetes.
Some people are so hungry they end up consuming large amounts of food in one sitting very quickly. What they do not realise is that this can lead to stretching of our stomachs over time, meaning that you will need to eat more and more food to feel full.
A bariatric surgeon friend of mine once mentioned to me that he often operates on people’s stomachs that are four or even five times larger than they should be due to years of being overexpanded. Luckily the stomach is a muscle and can shrink with eating smaller portions over time. The other thing to keep in mind about the speed at which we eat is that it takes around twenty minutes for the message to be conveyed from our stomachs to our brains that we are full. So slowing down the speed at which we eat means that the hunger centre in our brain will be switched off when we have had an appropriate amount to eat and we are likely to not overeat.