"Burning mode" refers to a state or mindset of intense focus and determination to achieve a goal quickly and efficiently. It represents a high level of motivation and drive. Full definition
If you use another sweetener such as honey, maple syrup or coconut sugar it is still healthy but will not put you in fat burning mode as there would be too much sugar. (drjockers.com)
Remember that lowering the blood sugar response to a meal can help to control insulin levels and therefore keep your body in fat - burning mode for longer... and prevent cravings too! (truthaboutabs.com)
When sugar doesn't reach your cells anymore, but you're in sugar burning mode, your body will always feel like it needs more energy (more food). (healthcoachfx.com)