If this was true, sugar cravings would disappear when taking antibiotics that kill those microbes.
The fact that this doesn’t happen should give you pause about this woo-woo theory of cravings.
The reason you crave sugar and fat and other tasty things is that they taste good. You evolved in a world where feeling rewarded and driven to consume more of these was beneficial to survival when food was scarce.
Clearly "tasting good" is not the primary driver behind all of this. Good taste is an incentive to satisfy something more primary, similar like sex feels good in order to satisfy procreation
> Good taste is an incentive to satisfy something more primary,
Covered in my comment above: The more primary drive is that those are high calorie foods. A drive to consume more high calorie foods is beneficial in times of food scarcity, like the past.
Cutting sugar doesn’t kill 100% of the gut biome either. It doesn’t kill gut biome at all, actually, it just changes some of the proportions. Those parts of the microbiome are most likely still there, just in different ratios.
Antibiotics are a far more powerful and faster modulator of gut biome, therefore if the above was true we’d see similar effects occurring more rapidly with antibiotics than diet.
The fact that this doesn’t happen should give you pause about this woo-woo theory of cravings.
The reason you crave sugar and fat and other tasty things is that they taste good. You evolved in a world where feeling rewarded and driven to consume more of these was beneficial to survival when food was scarce.