I would say yes and so do the author of the article with the same title as this blog post.
The author states that Mental Toughness includes:
1. belief in self
2. good work ethic
3. being self-motivated
4. high in self-regulation
5. being good at handling pressure
6. having good emotional control
7. able to monitor self
8. being resilient
And all these things combined, helps you overcome life's challenges to succeed in weight loss.
I can't agree more. It takes a certain mental toughness to persevere when you aren't seeing results, to say no to food that isn't healthy for you, and to exercise regularly - whether you feel like it or not.