When this man is feeling weird about his GF's response to his criticism, he asks Reddit:
About two yeas ago, my doctor had told me that I (m27 now) needed to lose some weight as I was a pre-diabetic and at high risk of developing cardiovascular disease.
Furthermore my BMI was really high and he said I would be increasing my risk of cardiovascular disease. Then for two years I worked-out basically 5 days a week, till I got into shape.
It was during my weight-loss journey that I met my girlfriend (f26), at the gym actually, and we went out for dates and we quickly got into relationship. After we got into a relationship however, things changed.
I continued to work on myself and I got into pretty good shape. By contrast, my girlfriend completely halted. She used to be a rock-climber and she completely stopped that. Now her physical activity has basically come to a halt.