Dieter (noun)

A person who follows a diet in order to lose weight or improve their health.

Origin:

20th century: back-formation from diet.

Examples:

1. The dieter carefully counted calories to reach her weight loss goal.
2. The dieter followed a strict regimen of eating healthy foods.
3. The dieter avoided processed foods and focused on whole foods.
4. The dieter was determined to lose weight and improve her health.
5. The dieter had to overcome many challenges to stick to her diet plan.