Three signals that you’ve eaten enough

You may not have spent much time thinking about what it means to have had enough food. It’s obvious, isn’t it? You stop when you’re full. If someone asks, “how do you know when you’re full?” you might respond that it’s just like asking, “how do you know you have a pain in your knee?” The answer is, “you just do.”

Of course there are different types of knee pain. Sharp and stabbing, dull and aching, and so on. In just this way there are different types of “feeling full” (though I prefer the phrase “had enough” to “full” and you’ll see why later). If we pay attention to these different feelings we get in our bodies when we’re hungry and not hungry, we can learn a way of eating that feels almost like a miracle; eating enough to be fit and healthy, without eating too much and getting (or staying) fat.

It’s time to delve into the murky world of psychophysiology.

Psychophysiologists study the conscious experiences we have when things happen in our bodies. Most of us, most of the time, aren’t aware that our hearts are beating. And none of us is aware that our kidneys have just downregulated urine production. Certain physiological tests, like scans, might be able to find these things out for us, but we can’t know these things just by feeling. Similarly, we’ve known since the 1960’s that injecting people with a hormone like adrenaline will result in different conscious experiences depending on what the person is expecting. Adrenaline, for instance, can be interpreted as “I’m excited” or “I’m scared” depending on the contextual cues. There isn’t a clean one-to-one mapping between our labels for our experiences — scared, red, happy, pain, full — and the physiological states in our bodies that make us use these words.

Scientists have known for a long time that people can be trained to recognise certain internal experiences reliably, and even to have control over things they don’t normally have control over. A great example is biofeedback, where external measures are taken using electrodes etc, and the participant is then given the task of learning to manipulate the number on the computer screen. So she might be told that she can learn to control the tension in her painful neck muscles, and then by hooking up a computer to measure neck muscle tension, she gets immediate feedback on whether she’s correctly targeting those muscles as she tries to relax them. Over time, she learns to control those muscles almost as easily as she can bend her index finger.

You don’t need a computer and an expensive psychophysiology suite to make use of this knowledge. The first thing is to learn that there’s more than one bodily signal for “feeling full” and if you’re like most people you probably call all of them “feeling full”. It’s time to learn some subtlety.

When we’re really hungry, having not eaten for hours, a few things happen. Our stomachs are empty, and might get rumbly, our sense of taste heightens, and our blood sugar is usually pretty low. (All these things are complex physiological processes, so that, for example, low blood sugar also means a slew of hormonal changes involving insulin, grehlin, and leptin, but that doesn’t matter for our sakes. What’s important is that they’re all tied up with low blood sugar and so we can use that as a decent label for what’s going on.) When we start to eat, lots of different changes go on in our bodies. We usually lump all these changes together and call them something like “getting full” but if you’re really careful, you can notice the different processes happening separately.

There are at least three components to feeling like you’ve had enough food:

Signal 1. Food tastes a bit less satisfying

Have you ever noticed that even a half-decent food tastes awesome when you’re really hungry? That’s because your body is fairly clever. It adjusts how you experience drives like hunger, thirst, and ahem… libido, according to your particular need in the present moment. If you’re really hungry, your standards are lower. (None of this would ever admit that this happens with libido, of course.) If you’re really really hungry, even low-fat cottage cheese might be palatable. Your favourite cake is sublime. It takes only a few bites, usually, for your taste buds to turn down the volume. If you take two, three, or four bites of something, and really really pay attention, you’ll notice that it rapidly gets less tasty, less satisfying, and less crave-worthy.

In this way, your taste buds are usually the first part of your body to start sending the “had enough” signal.

Signal 2. Blood sugar changes mean your body feels different

You know how you feel really sluggish if you’ve not eaten for hours? Some people even get a slight headache. You know how you feel that souped-up buzz after some sugar-laden treat? What you’re feeling, amongst other things, is your blood sugar levels going up and down. This is a pretty tricky signal to tune into. Most people find this the hardest signal to pay attention to. If you eat a high glycemic load food (lots of sugar, not much fibre or fat to slow down digestion) it can happen really fast, just a few minutes. If you eat a normal healthy meal, it can take twenty minutes or so. (This is where the “20 minute full signal” idea comes from I think. That’s really only a bit of an estimate and probably not the best way to think of it.)

There are some problems with this as a fullness cue, in my experience. First, people find it hard to tune in to, as I’ve said. Second, the signal is much stronger if you eat seriously unhealthy things (think cookies and cake). If you rely too much on the blood sugar feeling, or as some psychophysiologists call it, “body satiety,” then there’s a serious risk you’ll be teaching yourself to love sugary quick-hit food. (I have a pet theory that those of us who are very prone to being overweight have learned to love this quick-hit blood sugar rise, but I’ve no evidence for that yet, so I’m just going to leave it here in a side-note.)

Signal 3. Your stomach feels physically full, like a bag with lots of stuff in it

You know only too well that feeling of physical fullness in the stomach you get after a heavy meal. You know what I mean. After Christmas dinner you feel like if you put any more food in your mouth, your abdomen will burst. Most of us seem to think nowadays that this signal is binary. Empty or full. One or the other. It’s not at all, we’ve just stopped noticing the levels in between.

There are things you can do to re-learn what it feels like when your stomach is full, but not full-to-bursting. You can read about one of them here. Even without deliberately re-programming your brain, you can just start to notice feeling full. After each mouthful, just notice how full your stomach feels. And by the way, your stomach isn’t by your belly button. It’s higher. Much higher. Behind your ribcage. For most people, the feeling of fullness happens just behind the bottom of the sternum, behind the little indentation between your belly and your chest.

How do we apply this wondrous psychophysiology to real life?

Tip 1: Stop eating when you feel you even might be full.

When you even start to feel full, when you have even that slightest feeling of fullness between your tummy and your chest, STOP EATING. This is not a risky proposition because if you follow my advice, you’re going to be nice to yourself. You’re not going to beat yourself up for eating bad foods, and you’re certainly not going to eat so little that you’re always hungry. When you are eating, err on the side of too little, and stop the second you think you even might have had enough. If, in twenty minutes, you find that it actually wasn’t enough and you’re physically hungry again, then go and have a bit more food. It’s OK. You’re not supposed to be starving yourself.

Remember that if you just do this one slightly difficult thing — stopping when you think you even might be full — you can eat whenever you’re hungry. You never have to beat yourself up and go about feeling like you’re starving because of that new diet you’re on.

When you’re learning to do this over the next couple of weeks, you’re going to get it wrong quite a few times. Don’t beat yourself up. You’re changing a habit that’s been ingrained for years and years. It’s bound to take a while. You’ll probably find at first that your mind resists the idea and screams “I’ve definitely not eaten enough! I’m going to be starving later!” Say thank you to your old granny of a brain and just stop anyway. If you were wrong, and a little while later you’re hungry, reach into your bag and get that healthy snack you brought along just in case.

Tip 2: Especially when eating anything that’s a bit less healthy, really enjoy it, and when it no longer tastes great, stop eating. You’ve already had the best bit.

Sometimes you’ll want to eat a treat food — something you know isn’t great for you like cake, cookies, or ice-cream — and that’s OK. Allow yourself to eat it. Normal people, with a healthy weight and an untortured relationship with food, do eat cake and ice-cream. Sometimes together. What they don’t very often do is finish a two-pint tub of ice-cream or eat a whole chocolate cake. Sometimes. Not often.

So here’s tip 2. When you’re eating less healthy food, especially something you’re eating because you fancy the flavour, enjoy the HELL out of it. Really, really pay attention. Savour it. Like a wine connoisseur rolling a wine around the mouth. I’ve written a post on how to really enjoy your food this way, which might help. Enjoy it. Revel in it. Glory in cake. Or cookies. Or whatever. Eat it guilt free. AND just like a connoisseur, eat really really slowly. Savour each and every bite. The first bite will taste amazing. The second bite will taste damn good. Pretty soon, after maybe as few as three bites, it’ll taste good, but not great any more. That’s the point to STOP! Following this way of eating you can have cake whenever the spirit really moves you, so why the hell waste the calories eating cake that now only tastes goodish? You’ve just had the wonderful pleasure of it tasting amazing. It’s not going to get better than that if you stuff more in your mouth. Real true pleasure from food comes from eating something gorgeous when you’re at least a bit hungry. And your friendly local psychologist will tell you that we tend to remember the end of an experience more than we remember the start or middle of it, so if you keep eating and the pleasure is decreasing as you go on, you’ll remember that cake as being less satisfying than it really was to start with. If you keep eating once the pleasure level starts to drop, you’re actually destroying the pleasure you had earlier.

Again, remember that by following this tip, you can allow yourself to eat treat foods regularly. Not six times a day, perhaps, but most days. You no longer need to be the person can’t let themselves have a piece of cake at a birthday party because “I’m on a diet”. You can eat anything you want so long as you do this one thing: When it no longer tastes gorgeous, stop.

Last word: Be nice to yourself

When you were learning to ride a bike, did you just jump on and ride straight away or did you fall off a few times? Right. Like everyone else you took your share of bumps and bruises. But in the end you learned to ride without looking like a clumsy five-year-old. Learning any skill is like that. In order to succeed you have to be willing to fail. If you apply the two tips above, and screw up, don’t stress. You haven’t blown it. Just keep trying.