To encourage ketone production, the amount of insulin in your bloodstream must be low. The lower your insulin, the higher your ketone production. And when you have a well-controlled, sufficiently large amount of ketones in your blood, it’s basically proof that your insulin is very low – and therefore, that you’re enjoying the maximum effect of your low-carbohydrate diet. That’s what’s called optimal ketosis.
In what is perhaps the biggest buzzkill of all time, sex doesn’t quite count as cardio or burn a significant amount of calories: Women burn about 3.6 per minute. "It’s still a good idea," Dr. Seltzer says, citing the activity’s other benefits, like increasing the output of the neurotransmitters serotonin and dopamine, which naturally reduce food cravings.