If your stomach is not empty, food does not look as appetizing. When walking for weight loss, distance is important, not speed.
If it brings up negative emotions, there are plenty of other ways to monitor how your body is doing. Your lab results — for example, your blood sugar and blood pressure — are other helpful measures. If you really want to make sure you’re in ketosis you can check your ketone levels in the body by doing a breath, blood, or urine test.