The meal generator will determine the number of servings for each meal based on your preferences and nutrition targets. You can be sure that the amount to eat is always calculated with your nutrition targets in mind, even if it's calling for multiple servings. When you click on a recipe in your meal plan, the ingredient amounts are already scaled to the number of servings planned for you.
We don't currently have a way to force the generator to use one serving, as the flexibility to scale these foods up or down allows us to provide more preferable meal plans with reasonable variety and food combinations. The one exception to this is when you set a food to recur always for a meal, in which case you can select a specific amount that will always be generated for that meal. For example, if you have a daily coffee, you can set this to generate 1 cup every day. You can see more about this here: Using Recurring Foods to incorporate more of your preferred foods
That said, sometimes particular preferences selected on your account may limit the variety of options and result in unusually scaled-up portions. If it seems like the generator is suggesting unreasonably larger portions or never suggesting single servings, please reach out to us at [email protected]. We're always happy to take a look at your account and see if we can offer some suggestions to help out with this!