On one level, it's a relief to not have to think about what to eat or spend time in the kitchen but the problem lies in human nature - the second you're told you can't have something or, in this case, anything, that's all you want.
I miss texture. And chewing. And tastes other than artificial sweetness. It's not even like I'm craving burgers and cakes. Honestly - and weirdly - all I want is a sausage on bread.
Most of the Opti products are truly disgusting and everything has a vague chemical taste - I had a meal replacement bar that tasted exactly like how my dog's old rubber chew toy used to smell.
What I will say for it though, is it gets you used to a life in which everyone around you is eating and you're not. It's weird. It's especially weird in brown cultures where food is manaaki and aroha.
Already I'm making vague plans to catch up with people and realising that almost every form of socialising I know revolves around food and drink, from going to dinner to getting coffee.
As trivial as it sounds, that's been one of the few doubts I've had heading into this week: what my life will look like when food isn't such a major part of it because food and drink are how we celebrate, commiserate and mark everything in between.
However, any real doubt I had disappeared last week when I injured my knee.
I couldn't move without unbearable pain and had to call the ambos, who had a tough time figuring out how to manoeuvre me out of the house and in and out of various chairs and beds, because I couldn't bear any of my own weight.
I then had an extra hour-and-a-half's wait in A&E because they had to search for a leg splint that would fit me as they only had smalls and mediums.
That injury probably wouldn't have happened if I weren't so heavy and the logistical nightmare certainly wouldn't have happened if I weren't so large.
At another time in my life, I'd have been horribly embarrassed but thankfully I've made peace with my fatness. It was, however, a wake-up call. What if that was a life-threatening situation and I got in my own way of receiving medical attention?
Like I've said, it's all about weighing up costs and benefits and I'm pretty sure health and security outweigh Sunday brunches.
So, as I write, I'm preparing to head into hospital with no second thoughts or nerves and, by the time you read this, I'll be in recovery.
At this point, the only thing to fear, awful diet shakes aside, is the unknown.
But that's also the exciting part.
Siena Yates' column will return fortnightly, from July 11.
