From what I have seen on this forum, and I have seen no evidence of this in the studies, people trying to lose relatively small amounts of weight, who are not severely obese at the start , seem to get more side effects and more effects at lower doses , than I would expect. And the research is not that helpful as most people were more overweight in the studies. There is no doubt at all that the metabolic state in severe obesity is quite different in a lot of ways , so it sort of makes sense.
I cranked the dose of tirz from 1mg to 15 in a month, without issues, no I am not recommending it, but I had already lost 70 kg at that point.
For the OP the fact that calorie intake dropped to 600 /day when you started at 1mg suggests you are pretty sensitive to the drug, so being more careful is probably sensible. Worse side effects are always possible with any dose increase at any stage, but increasing slowly probably is likely to make them less sudden or severe. If you did not notice the effects increasing over the last 4 weeks, then if you increase to 1.5mg and you still have no side effects and are still hungry then you probably do not need to wait 4 weeks to increase to 2mg, 2 weeks is probably fine, given that 2mg is the standard starter dose and not thought by the company that makes the drug to be risky.