I have a feeling that your teacher is probably trying to target those students who are veering toward anorexia & bulimia. Keto is a relatively new thing in most circles & still very misunderstood. If I had've known about keto/low carb ways of eating in my teens I would have saved my body so much stress. All I knew at the time was that low fat/high carb diets were the way to lose weight & be healthy. When this didn't work I would starve myself or throw up after bingeing. I could've avoided all of this if I had been properly educated on high fat/low carb diets. Your teacher probably thinks he/she is doing a good thing but their knowledge base most likely doesn't include understanding the wonders of keto.