In my last blog post I introduced you to the concept of time restricted eating and the benefits that can come from following this eating strategy. Just in case you forgot or missed the last post (click here to read) , the three benefits of time restricted eating are reduced decision fatigue, reduced calorie consumption and improved circadian rhythm. As I stated last week, by reducing your decision fatigue you will have increased will power and energy which will make it easier to adhere to your diet until it becomes a habit. And once it becomes a habit then it becomes a part of your life, just like brushing your teeth, and you brush your teeth right?
Not only will reducing decision fatigue improve your diet, but it will also allow you to focus on other aspects of your life; like work, family and exercise! But enough about decision fatigue, it’s time to found out why time restricted eating reduces your calorie consumption.
But Erik I already know the answer to this, if you reduce your eating window obviously you will eat less calories, says everyone.
Yes, the above statement is true, but there is more to the story then just a smaller eating window. The main reason time restricted eating works is due to its effects on hunger. Once your body adapts to this eating strategy you feel less hungry and will avoid the dreaded feeling of being hangry.
There are many hormones and neurotransmitters that play a role in hunger and fullness; ghrelin, leptin, insulin, neuropeptide Y, dopamine, cortisol and serotonin are just a few. For today’s post, I will focus on insulin and its effect on hunger. In short, insulin is secreted from the pancreas any time you consume carbohydrates, protein, or fat. Simple carbohydrates (sugars, processed foods) secrete the most insulin followed by complex carbohydrates (fiber, vegetables, fruit), proteins and then fats. However, it is important to realize that we all have different responses to food. For example, the study on the graph below shows just that:
Now that we know we can’t generalize diets and have to make it specific to the person we can proceed. If you have been near a computer in the last ten years then you have heard about the low carb revolution and the terrible, fattening effects of insulin. The people pushing this ideology were correct that insulin can cause weight gain, but they were wrong in stating that it is solely responsible for the obesity epidemic. In the low carb dieters eyes all you had to do was reduce insulin and the weight would melt off your body. Granted, this did work for some, but it wasn’t due to a reduction in insulin levels. It was due to reduced hunger and calorie consumption. Below I will give you a quick summary on how insulin promotes hunger and fullness.
When you consume nutrients (carbohydrates or protein) your body breaks those down starches and amino acids into glucose (sugar). Insulin is then secreted from the pancreas to drive glucose into the cell to get rid of the high glucose level (high blood sugar) because of how toxic it is to the body. In fact, high blood sugar is so toxic to our body that too much of it in the blood can kill you! And this is why we need insulin to survive because it plays an important role in opening cells and delivering glucose into the cell, i.e the cell is locked and insulin is a key that unlocks it. Therefore, insulin is needed for the body to function because it clears out the toxic glucose by giving your cells the energy they need to function. Not only does insulin deliver energy (glucose) to the cells but it also contributes to muscle growth and proper cellular function. Remember, insulin is anabolic which means it contributes to muscle growth. This muscle growth leads to a bigger muscle which allows your body to store more glucose (i.e more carbohydrates) in the cells of the muscle, but you must lift weights to take advantage of it.
Since the the secretion of insulin pushes glucose into the cell, it turns off the fat burning process by turning off hormone sensitive lipase (HSL). HSL is used to break down fat into fatty acids to be used for energy but since the cell has glucose available, there is no need for this fat breakdown to occur. The low carb dieters saw this mechanism and concluded:
1) When insulin is elevated, the breakdown of fat is decreased
2) When insulin is low, the breakdown of fat is increased.
They took this idea and howled to the moon,
Ah ha! We have found the cure!
But unfortunately insulin is not too blame for the obesity epidemic. There are two sides of the coin with insulin, the two sides are insulin sensitivity and insulin resistance. Put simply, if you are insulin sensitive then you will need less insulin to get the job done versus someone who is insulin resistant. If you leave a light bulb on 24/7 it will get burnt out and the same thing can happen to your pancreas (i.e the organ that secrete insulin). This insulin resistance is driven by frequent carbohydrate dense meals which forces your body to be dependent on glucose for energy. This dependence overworks your pancreas and ruins your body's ability to use insulin effectively.
Do you remember how I talked about high blood sugar being very toxic to the body?
Well you are in trouble if you are insulin resistant because you won't be able to lower the glucose levels in your blood. When the brain senses higher blood glucose levels and can't rely on insulin to lower them it has to take over and save the day by converting the glucose to fat. The brain does this because if it didn't get rid of the glucose in the blood you would die. So yeah, having proper insulin signaling is critical to living a long healthy life. And the problems from insulin resistance don't end there. Not only does insulin resistance lead to excessive fat gain but it also puts your hunger on a roller coaster due to the spikes and drops in blood sugar. Throughout the day you will go through peaks and valleys from craving everything on the menu to craving nothing.
Many people go through this phenomenon every single day and it is the main reason why most people blame carbohydrates for weight gain. Luckily we can fix all of this with time restricted eating because it forces you to fast daily. This fasting mechanism between meals gives your pancreas a break and allows your body to become more insulin sensitive. This can be accomplished by consuming your meals in either a 12,11,10,9 or 8 hour window preferably earlier in the morning versus late at night (read more here). Most people are like Pacman and constantly overeat. They never allow their body to rest and digest, they consume food 24/7 and expect to lose weight because once upon a time we believed that frequent small meals sped up our metabolism, but that couldn’t be further from the truth (read here) .
Here's the truth, if you want to lose weight you need to take a break from eating and give your pancreas a break, this is non negotiable and must be practiced 4-5 days a week for optimal health. After all, we do take the weekends off from work and we do take rest days from exercise, so doesn’t it make sense to give our digestive system a break?
Stay tuned for my next post where I go over the most important benefit, improved circadian rhythm.