This may not be the problem but it could be.

Do you know if you are in ketosis? If your carb levels are low enough, you likely are in ketosis. When you go in ketosis there are markers that show you are in fat burning mode. One is betahydroxybuterate in the blood. That is what blood ketone test strips test for. You have ketones in the urine, especially early on in the process before your body has gotten used to burning them efficiently. The excess ketones spill over into the urine.

But what I am getting to is acetone. Acetone is also a byproduct of fat metabolism and it is expelled through your lungs and breath. You could be smelling this acetone. When I first went on a ketogenic diet I could tell when I was in ketosis by my breath. It almost felt to me like I had "hot" breath. After a while I got used to and I no longer notice it. Once in a while I will still notice it but not usually.

I don't know if that is what you are smelling (different people have wide range of ability to smell things) but it could be. Being only a month into it, that would be the time frame when you could be getting fat adapted really well with the fat furnace burning at a good rate. With the weight you have lost, you definitely are in fat burning mode.

John