There is a hormone called leptin. It is not your friend.
It was relatively unknown until fairly recently - around the turn of the millenium.
We previously thought that our fat cells were mostly inactive - that they were just storage depots for lipids. It turns out they have some activity, and one of them is the creation of leptin. If I recall correctly, the fat cells produce leptin all the time, but they also put out of boost of it when they're actively storing fat - that is, after you eat a big enough meal to be storing lipids in your fat cells.
Leptin gets into your blood, and goes to your brain. It suppresses the food drive. This is a feedback loop that makes some sense; if you have more fat, you produce more leptin, and this tells your brain to cut back on the appetite and hunger - you don't need to eat as much.
The catch is that the brain gets accustomed to a given level of leptin. When an individual is very obese, they produce a lot of leptin - and the brain gets used to that level of leptin as "normal."
Then, when you lose a significant amount of fat, your leptin levels also decrease. To your brain, this lower level is abnormal. The normal limiters on the hunger drives get turned off. Your brain wants you to get back to normal.
This is a big part of why it's so hard to maintain weight loss. Your brain is used to being in a fatter person's body. We don't know how long it takes before it gets used to being in a smaller person's body, but until it does, you will psychologically and physiologically react like a person whose body is desperate to regain lost weight.
Lyle McDonald describes the brain's acclimation to high leptin levels as similar to becoming addicted to a drug. Then, when you lose a lot of fat and the level goes down, you can look at the response you have as going into a kind of slow-motion "withdrawal." It's not food withdrawal... you still get food every day... it's fat withdrawal. You brain goes into a sort of leptin withdrawal, giving you cravings and hunger, because pumping lipids into the fat cells gives it some relief. But it's a slow-motion withdrawal, because this will last many months (years?) after you've lost the weight.
As with other drugs, we know that we begin to experience relief as soon as we decide to indulge... before the leptin starts to flow, before we start to eat, before the food even arrives, the decision to start the process in motion gives real relief. The desire is powerful, and it's real.
It does go down over time, but like other addictions, starting on the drug again can easily spiral out of control. So if you "let yourself go" over the holidays or a stressful period, for example, and you eat enough to get your fat cells pushing out more leptin, you're giving your brain the drug it craves. For most people, starting on the drug again leads to craving more of the drug, and the spiral begins anew.
So, why am I writing all of this? Besides me being a windbag, that is?
Because I'm having the same struggle as you are. At the end of the day, I know I'm not really hungry - I don't need more calories or nutrition. But I'm feening for food. I'm thinking about what to have as a snack. Or a meal. And it's very hard to stop myself.
I lost a small fraction of the amount of fat that you lost, and then I regained a bunch of it in recent months after a serious back injury, and I'm caught at the top of that "spiral." Reading about your situation reminds me that I'm in a similar place, albeit in lesser degree. If it's hard for me, I imagine it's profoundly difficult for you.
I'm now going to try thinking of my leptin at the end of the day. I'm going to think about myself as if I'm a "fat addict" at the end of the day, and try to use that to help myself overcome the powerful psychological urge to eat more. This isn't about fat-shaming; it's about giving myself more willpower by being consciously aware of the brain chemistry that is conspiring against me.
End note: I don't mean for the analogy to drug or alcohol addiction to diminish those very real addictions, nor to make light of them. But we can learn from them - especially from the willpower of those people who manage to overcome them.