GLP-1 and Habits: Use the Quiet to Rewrite the Loop

If you’ve ever listened to experts in behaviour change and habits, they say that every habit has three parts: a cue that sets it off, a routine (the behaviour itself) and a reward that makes your brain want to repeat it. Run that loop in the same setting often enough and the basal ganglia, a deep and very old part of the brain, takes over so you no longer have to think about it. Research suggests something like a third to 40% of what we do each day happens this way. You didn't consciously decide to eat the chips. And perhaps you were intending not to! But being at the table, having the bowl right there, and the fact it was 5pm were enough of the cues that took the decision away.

Old habit loops don't really get deleted. They get overwritten. The most reliable way to change one is to keep the cue and the reward and swap out the routine in the middle. For example, if you really want to switch off at the end of the day, and the glass of wine is what you usually grab as a way to do that, changing that routine is the thing you need to do. I know. Easier said than done. However, a stressful end to the workday is the cue, switching off is the reward, and the wine (or the pantry raid) is simply the route you've always taken to get there.

GLP-1 medications fit into this conversation as they turn down one of the loudest cues in the loop: hunger and food preoccupation. With that cue muted, new routines are easier to practise, and with that is an opportunity to break out of those habits that no longer serve you. Using the window of time provided to build habits that align with your goals. That said, while it would be wonderful to say that this opportunity therefore means the habits you create will allow you to effortlessly come off the medication, the current evidence doesn't fully support that. Trials where people stop the drug abruptly show weight tends to come back, faster than after diet and exercise programmes. Real-world data are more encouraging, particularly for people who taper, keep support in place or have a plan.

So habits are part of a long-term plan, and coming off medication is a decision to make with your prescriber when the time is right for you, however the timeline itself isn’t fixed. I reminded a client of mine that we had spent 9 months of practicing these habits and, though they feel durable in the moment, habits are actually quite flimsy, only because the three decades before that have been imprinted in the brain. That means the more opportunity you have with the food noise dampened down to override those embedded habits, the better chance you have of long term success.

GLP-1 or not, the people who change their patterns are the ones with structure. "Lose 10 kg this year" is an aspiration. A plan names the cue and the new routine: "When I get home from work, I'll change and walk around the block before I open the fridge." These if-then plans are called implementation intentions, and across hundreds of studies, if-then plans reliably improve follow-through, with the strongest effects when you're genuinely motivated and have rehearsed the plan. Evidence is stronger for adding a behaviour (i.e. go for a walk) than it is to stop one (‘I won’t turn on the TV’). Then track it. Habits run below conscious awareness, so you won't notice them on your own. A quick daily check (did I do it, and if not, what was different today?) turns vague frustration into information you can use.

Your brain responds far more strongly to rewards that are imminent. A goal weight by Christmas can't compete with the doughnuts in the staffroom at 10am. So build in something immediate: a tick on the calendar, a note in your phone, a magazine you want to read, a movie you want to see. Try to make the reward align with the overall goal (i.e. don’t make it a block of chocolate). It works because the same reward circuitry that responds to a sticker chart is still very much running the show.

It’s interesting to think about the difference between what people say they want, and their actual behaviour. Economists talk about stated preferences (what people say they want) and revealed preferences (what their choices show they want) which is useful here I think. The part of you that decides who you are watches what you do (revealed preferences), not what you say (stated preferences). Telling yourself you want to be healthier changes very little. Training three mornings a week for a couple of months starts to make you someone who trains, and other choices tend to follow. A GLP-1 medication can help the right person close the gap between these so they are interchangeable.

The thing with habits though, is that they may feel permanent when you’re in the thick of it, but they can be flimsy. Doing something for eight weeks feels like a lifetime, but you’ve actually got decades of doing things in a different way that will make it harder to make actual change. That is good and bad, right. Because while it means that things are more durable than we think, it also means with the right structure, they're far more changeable than they seem.

1. Swap the routine, keep the cue and the reward. Old habits are overwritten rather than erased, so find a new behaviour that delivers the same payoff in the same moment.
2. Quieter food noise is an opportunity, not an exit strategy. Use it to build protein, training and eating habits, but current data show weight typically returns after stopping medication, so plan any change with your prescriber.
3. Write plans, not resolutions. Name the cue and the exact new behaviour, then track it daily so you can see what's working.
4. Reward the behaviour today. Immediate rewards train your brain far better than a goal months away, and identity follows repeated action.