I'd first start by questioning what evidence you've seen that would convince you that calorie restriction is a good idea?
I've seen zero studies in humans that would indicate this. The negative side effects are huge, and little evidence for significant gains in longevity.
There was a good discussion of this on the SSC blog last year: https://slatestarcodex.com/2019/12/12/acc-does-calorie-restriction-slow-aging/
With regards to meal timing, I've been keeping an eye on the research for over a decade, and in short it makes very little difference.
Quality and quantity of food are what really matter.
That said, both the research and what I've seen anecdotally do indicate that there is huge individual variability in how people do on different diets.
Typically by following some arbitrary rule (I.e. avoiding food group x), dieters inadvertantly reduce their calorie consumption.
Most diets ultimately fail either because people miss said food group and return to eating SAD or find some way to "cheat" (gluten-free cakes, vegan cheese, etc), not realising it was the calories that were the issue, not the "evil" food.
Time restricted eating plans work in much the same way. By limiting the hours during which you allow yourself to eat, you typically reduce your calorie intake, particularly in the short term.
As with other methods, however, we humans are very good at adapting by eating bigger, more calorie dense meals over time to compensate!
My personal experience of various different modes of intermittent fasting is that it does have some advantages:
- It teaches you to recognise true hunger
Often we eat when we're not really hungry. After a few 24 hour fasts it becomes much easier to turn down junk food if it's the only option and wait till you can find something better.
- Less cooking and washing up
Though I actually enjoy the cooking part, eating just 2 x per day does save considerable time and effort.
- Can eat larger/more calorie dense meals.
Of course you have to be careful not to over compensate! But if you're going to eat 2000 calories personally I prefer 2 x 1000 meals to 4 x 500.
All the above for your average person.
If you're a high level athlete, or a bodybuilder, there's further questions of meal and micronutrient timing around training, and yes if you're looking for every tiny gain in physique and performance these can make a difference, but I don't think for most people it's worth worrying about.
That is largely what I'm getting from Sinclair's Lifespan. What it seems to do, if I'm following his claim, is the restricted diet puts the body in a stressed mode (not malnourished state, that is to be avoided). The switches on come cellular activity that shift energy from cell division to cell maintenance and cleans up a lot of the garbage (malformed and miscoded proteins).
He also suggests that the other thing to diet wise it reduce the intake of some of the essential amino acids. We get too much of those and they are all associated... (read more)