I assume you mean fasted state.
If so, it depends, if you have "plenty of fat" to spare, then ok. If preservation of lean mass is priority, and you are currently lean, then no.
And when I mean fasted state, I am talking first thing in the morning. Amino acids are vital for fat burn to occur at all, if you understand the mechanism of how fat is burned. First thing in the morning, though FFA's are higher due to liver glycogen, they are used up quickly.
For continued FA useage, if amino acids are not available, then there is only one place to get them.
On a starvation....or a high fat/low carbohydrate/low protein diet(which could be from an overnight fast also, there is the chance amino acids will not be available sue to "starvation") will cause other problems......for fats to be converted to citric acid, oxaloacetate must be available. Without oxaloacetate, citric acid cannot be formed and acetyl-CoA cannot be further processed.
Oxaloacetate can be produced from the breakdown of certain amino acids. However a person on a high fat/low carbohydrate/low protein diet(again read lean, overnight fast), will need to use the oxaloacetate for gluconeogenesis.
Fatty acid breakdown however must still occur for ATP generation and acetyl-CoA will need to be processed through an alternative pathway. This pathway leads to the formation of ketone bodies.
The amino acids will need to be derived from muscle tissue, leading to muscle wastage.