There are so many diets, cleanses, and lifestyle changes out there with tips to help you 'trick yourself' into eating less than your body needs. Many of these tips involve tips to make you ‘feel full’ with very few calories but while this may act on stretch-receptors in the stomach to make your stomach physically full, satiety and appetite is a lot more complicated than that!
Instead, these 'tricks' usually lead to feeling hungry and deprived! (Note: I’m not going to list any of them to avoid triggering anyone who might be struggling or giving them ideas because the truth is, many of these behaviours are common in eating disorders.) This eventually leads to over-eating and feeling out-of-control around food. The thing is, that isn't because something is wrong with you, it's because you can't 'trick yourself' into eating less than you need. Today, I'm breaking down why that is.
So let's start with the basics of hunger and appetite. Essentially, your body's energy needs are pretty tightly regulated based on your hunger- your body has an amazing system to tell you how much to eat based on your needs, which I'm going to outline in a minute! This also does a much better job than counting calories since our energy needs actually change day and the truth is both calorie equations and calorie counts are just estimations- while they may give a general idea of your needs, they're not perfect!
I know I'm going to get the question "if our energy needs are so tightly regulated, then why do people gain weight?" There are many factors at play, including the fact that many people try to diet their way to a weight that is lower than their natural set point because we live in a society that values thinness. Dieting (or 'lifestyle change', or however you want to talk about restricting intake) is actually a predictor of long-term weight gain so part of the answer to why people may gain weight above their genetic set point is actually dieting. We’re taught that we can’t trust our body’s hunger and cues and we try to override them to look a certain way, which doesn’t work. (For those of you making the health argument for weight loss, you can check out my post on the matter here.)
How is our hunger regulated?
Basically, there are a number of hormones and feedback loops that tell us when we need to eat and when we’ve had enough to eat. There are hormones that make us feel hungry as well as hormones that tell us we’re satisfied on top of the physical stretch receptors in our stomach that tell us when we physically feel full. I’m going to go into some of the major hormones here with some information on how they work to give you an idea of why trying to fill up on volume to activate the stretch receptors to trick your body doesn’t work, nor does trying to just eat less than your hunger is telling you!
I also realize that for someone engaging in dieting and trying to change their body, this whole idea can seem downright depressing. My thought here is this: we can be irritated and discouraged that our body increases hormones to increase your eating when we try to restrict and get frustrated with the fact that pursuing weight loss doesn’t work out so well or we can think of it this way: your body knows what it’s doing when it comes to eating so you don’t have to stress so much about it! You don’t need to count calories and stress about the amount you’re eating because your body has it under control! You can trust your body.
Let’s talk about what it’s doing and why you can trust it! I'm going to go over the highlights -how your body regulates hunger and appetite is even more complicated than what I'm listing and in truth, there might still be factors that affect our appetite that haven't been discovered yet!
Ghrelin is probably the best known hunger hormone and is released primarily by cells in the lining of your stomach. Ghrelin gets released when energy levels are low and is one of the main ways your body says “I’m hungry, please feed me now!”
When individuals induce weight-loss in the short term by reducing their caloric intake, ghrelin increases, which causes them to feel more hungry. This is part of the reason why in the long term, weight loss strategies are generally unsuccessful. It isn’t due to poor willpower or lack of control, it’s your body trying to protect you from starving because for thousands of years, maintaining energy stores meant you would survive!
One side note for ghrelin is that along with going up when you aren’t eating enough, it also goes up when you’re not getting enough sleep! I’ve written about the importance of sleep when it comes to eating and health and some tips to help improve your sleep here.
One of the lesser-known hunger hormones is Neuropeptide Y, which seems to particularly increase our drive to eat carbohydrate. There is some research suggesting part of the feedback loop for this hunger hormone (what tells our brain it doesn't need to produce the hormone anymore) is what we call 'orosensory' meaning feedback from your tongue that you have sweet food in your mouth might be what causes this hunger hormone to go down! Leptin (see below) reduces levels of Neuropeptide Y, which is part of how this satiety hormone regulates appetite.
That feeling of being 'addicted to carbs' when you try to go on a low-carb diet may actually be due to Neuropeptide Y- our body needs carbs since our brains and red blood cells rely on them for fuel so if you're not getting enough, this hormone will make sure you're getting enough!
Another interesting note with Neuropeptide Y is that some research suggests it is associated with increased stress levels and cortisol, which is a chronic stress hormone. In other words, instead of trying to restrict your carb intake, finding a way of managing your stress is probably a much better way to go!
Our body has a complex system telling us when we we're satisfied!
Leptin is probably the best known satiety hormone, which is produced by fat cells and acts on a complex system of neurons in the brain to reduce appetite. When individuals diet and lose weight, leptin levels decrease, which leads to an increase in appetite.
There is a lot of talk about the idea of leptin resistance as a cause for sustained weight gain since people in larger bodies have high levels of leptin but this may not lead to a decrease in appetite and eating but we need more research on this. What we do know is that when leptin levels decrease, regardless of body size, appetite and eating goes up.
Leptin levels are also affected by sleep deprivation! When people don't get enough sleep, leptin levels decrease, which increases appetite. That means a lack of sleep has a double whammy for your appetite- a main satiety hormone goes down and a major hunger hormone goes up! Another reason to put a focus on getting a good quality sleep.
Cholecystokinin and Peptide YY
When we eat protein and fat, two hormones that make us feel satisfied, Cholecystokinin and Peptide YY, slow down how quickly food leaves your stomach. That's part of why you feel satisfied for longer when you put some peanut butter on your toast as opposed to eating two plain pieces of toast. This is also a part of why adding some fat and protein to your meals can help regulate your blood sugars better- food is taking longer to get to your intestines where the food is broken down and absorbed!
Convinced now that your body knows what it's doing?
The truth is that I really just scratched the surface here in terms of what regulates appetite. It is even more complex than what I listed here but hopefully this gives you a pretty good snapshot of what is going on. Dieting interferes with our body's appetite control and research shows ~33-66% of people gain back more weight than they lost through dieting.
So if you're not counting calories or weighing portions what can you do instead? You can learn to trust your body because as you've hopefully seen, it knows what it's doing! I know that's a scary thought to learn to 'listen to your body' instead of dieting and food rules but if this is something you're interested in, you can check out my services page to find out more information about working with me!