There are 18 words that start with 'diet'.
| diet | diets | dieted |
| dieter | dietary | dieters |
| diether | dieting | dietetic |
| diethers | dietaries | dietarily |
| dietetics | dietician | dietitian |
| dieticians | dietitians | dietetically |
Note: These 18 words that start with 'diet' are found from the USA & Canada version of the tournament Scrabble word list.