You eat what your brain tells you to eat
Have you ever opened a bag of chips planning to have a small snack, only to find yourself peering into an empty bag, a few moments later? (By the way, you should always put a snack in a bowl and put away the bag before you start eating …)
Your brain is to blame. Our rational, conscious brain thinks it’s in charge. “I eat what I want, when I want it. And I stop when I want to”. But, once again, the conscious brain is being influenced or controlled by physiological forces that we’re not even aware of.
As you are learning, deeper brain physiology drives what, when, and how much we eat — along with its co-pilots of hormones, fatty acids, amino acids, glucose, and body fat. For the most part, our conscious selves just come along for the ride.
The basics of weight regulation are linked to intake, and intake can really be broken down into two stages: why do we start to eat, and why do we stop eating.
We eat for two reasons
Eating for fuel / Belly Hunger / Homeostatic eating:
We eat to get the energy our body needs, and to keep our biological system balanced (aka homeostasis). Sometimes this actually manifests as a feeling called “hunger” that you feel in your belly …
Emotional Eating / Head Hunger / Hedonic eating:
We eat for pleasure (aka hedonism), or to manage our emotions. It’s not our body that needs fuel, it is our brains that think we need fuel. Unfortunately, this also sometimes manifests as a feeling called “hunger” that you feel in your belly …
Most times, when we eat, it is a mix of Belly and Head eating. Belly Hunger is best described by what causes us to stop eating.
Why do we stop eating?
Once we’ve started eating, what makes us stop? This is in part influenced by satiation — the perception of fullness you get during a meal that causes you to stop eating.
When we eat a meal, two physiological factors work together to tell us to put down our fork and call it quits: belly expansion and hormonal satiation.
Belly Expansion (Gastric distension)
When empty, your stomach can only hold about 50 mL. When you eat, the stomach can expand to hold 1000 mL (1 liter), or at the extreme end, 4000 mL (4 liters or 1 gallon). Your stomach is designed to stretch and expand, which is called gastric distension. Your stomach is also designed to tell your brain about how much stretching is happening. As your stomach expands to accommodate the incoming food, neurons in your stomach send this message to your brain.
Here is where you can use a trick. If you choose more nutritious yet low-energy and high-fiber foods, such as vegetables, beans, and legumes, because these take up more stomach space, they can help us feel full, though we’re eating fewer calories.
Hormones are more than just the sex hormones, estrogen, testosterone, etc. that people talk about most commonly. For example, insulin is a hormone. Hormones are used by the body as messengers.
While you eat, your GI tract and related organs (like the pancreas) tell the brain that food is coming in by sending them messages via hormones.
** Important Note: Many of these hormonal messages stick around. They can tell us to eat less at later meals, too. This is why you should think about your food choices and eating habits in the long-term — over the course of a day, a few days, or even a week. For instance, a high-protein breakfast might prevent you from overeating at dinner. Some of the more important of these hormones are:
- Cholecystokinin (CCK): When we eat fat and protein, the gut releases CCK, telling your brain to stop eating.
- GLP-1 and amylin: Recent research indicates that GLP-1 may be a unique, and the most important, satiation hormone. It seems to stimulate the production and release of insulin (a powerful satiation/satiety hormone itself) and slow down food moving from the stomach into the small intestine, among many other impressive mechanisms. Similarly, amylin is one of the few satiation/satiety hormones shown to actually reduce food intake.
- Insulin: When we eat carbs and protein, we release insulin. This tells your brain that nutrients are coming in, and eventually tells it to stop eating.
- Leptin: A hormone that is released by fat tissue. Leptin tells the brain how much energy we’ve just consumed and how much excess energy we have stored up (as fat). The more body fat we have, the more leptin in our blood. Leptin is at the heart of our body’s system for managing our long-term energy and nutrient needs: the leptin feedback loop. We’ll talk more about the leptin feedback loop later.
Now that we (kind of) understand why we stop eating, what makes us start eating in the first place? (bet you’ve never asked yourself that before …)
Why do we decide to eat?
Hunger and eating is shaped by many factors, including:
- Our genes
- Social cues
- Learned behavior
- Environmental factors
- Circadian rhythm
- Our hormones
- There is a hormone called ghrelin, the “hunger hormone”, that stimulates our appetite. It peaks just before meals, and falls during and immediately after eating. Yet ghrelin is not the only factor in hunger or the decision to eat. For example, research shows that mice without ghrelin still eat regularly, just like the mice with ghrelin.
- Our emotions
Most of the factors listed above are fairly self-explanatory, so let’s look deeper into just one of these factors for now: Emotions.
When you feel “mysterious hunger”, it is likely caused by emotions. What is “mysterious hunger”? It’s like this: have you ever been hungry… but not really hungry? Like you’ve just finished a big meal, but there’s something inside you yelling “Dessert!” Or you’re eating something that doesn’t taste all that good, but you keep eating it, and eat the whole bag? This is mysterious hunger. And you do really feel it.
So, you know that you’re not hungry, but you are hungry. We can call this mysterious hunger, or, to simplify, let’s call it Head Hunger, because you know that you’re body isn’t hungry.
When you feel Head Hunger, you can give into it, or deal with it. Obviously, the healthier option is to deal with it.
Dig Into Head Hunger
You probably know yourself well enough to know what causes you to feel Head Hunger: feeling sad, bored, angry… But what if it is less obvious? What if the usual over-eating explanations don’t apply? That’s when you need to dig in and find out what is really going on, because emotions are tricky. We feel them throughout our body, often in places we don’t expect. Like our stomachs. And, sometimes it’s easy to mistake these emotions for hunger.
In order to sleuth-out a non-obvious hunger, you need to assume that wanting to eat is just the last link in a chain that stretches into your past. It might feel like you’re hungry now, but maybe you walked past a good-smelling bakery 15 minutes ago and forgot about that. Or maybe something stressful happened this morning.
When you find yourself struggling with Head Hunger, here are a few tips to help you deal with it:
- Begin by assuming some thought, belief, and/or emotion is driving this, even if you don’t yet know what it is.
- Look for where your emotions are in your body. “Scan” your body from head to toe, observing any signals or physical feelings you notice. Observe only. Don’t analyze. Right now you are gathering information.
- Wait. Don’t rush to explain things with your immediate response, e.g. “Oh it must be my mother issues because blah blah blah” or “Oh, it must be because I had no protein and only 20 g of carbs.” If the answer pops up quickly, that’s your brain. Your body is slow and quiet with its signals. You must wait. At least 30 seconds, ideally 60.
- Remember that emotions can feel like hunger. Yes, it’s weird. But so is an elephant’s trunk and Nature made both of these things possible.
- Don’t “should” yourself or rush to judge the feelings. Let them come even though they seem stupid. Just be a little distance away from yourself and observe, like an anthropologist with a clipboard.
- If you feel a feeling, ask yourself how the situation you’re in might relate to a perceived threat to your own identity and values. Ask yourself, politely and conversationally, “Oh, OK, that seems important to me? Why?”
- When you get a response (again, wait – the body is slow), ask some more. “What’s that all about? Why is that important?” Keep asking, then wait and watch the body’s response. It’s like playing the getting warmer-getting colder game. “Is it this? Hmm, no. Is it that? Ah yes, that seems more significant.”
- Give yourself a few minutes to experience whatever emotions you’re experiencing. Check your watch if you need to, and allocate 5 minutes to this project. Unlike houseplants, ignoring feelings doesn’t make them go away. You might as well turn and face them. Roll around in the mud with the feelings for a few minutes. If you’re sad, cry. If you’re angry, chomp your jaw and growl like a pissed-off baboon. If you’re anxious, run around in circles like Homer Simpson.
- Work backwards along the “chain” for more clues. What were you doing just before you felt this? Who was with you? What was happening? What about an hour ago? This morning?
- Take 10 deep breaths. Exhale using a slow 5-count. Try to empty your lungs completely. If necessary, release the emotion you’ve been sitting with. Just let it float off, like a soap bubble.
- Once you’re done, notice whether your hunger has changed. If so, how? If not, how not?
- If you can’t find a private place to do this (e.g. at work, with kids running around), sneak off to the bathroom. If you keep the bathroom fan running, nobody will hear you whispering!