Portion plates have been used for some time to help people lose weight. They remind people to increase their serves of low carb vegies and reduce the meat and carb portions when serving dinner. Research has now been done to document how people found using them.
A UK study used crockery and serving spoon sets for people in a weight loss program. People in the study were happy to use both but the plates were used more often. The research showed that the plates reduced self- servings of chips and potato and increased serves of low carb vegies and salad. 
By reminding people to reduce their carb serves, these portion plates have "the potential to induce modest loss" and are simple and inexpensive.

These are the plates used in the study from the USA (Precise Portions) and include a drinking glass. The Australian plates I stock are below. They look quite different but the principle is the same. It would be good to have feedback from people who have used any of these before and if they have helped them. I certainly find they help all my clients who use them! 

Here's the link to the research-
​https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/acceptability-and-potential-effectiveness-of-commercial-portion-control-tools-amongst-people-with-obesity/1EE7393072C13C96CB8B66B90D61AEC4/core-reader 

Many of my clients tell me that they eat good food, but that they eat too much of it. This is why I bought my plastic food models. Love them or hate them, they do show clearly how much to eat. 
Many people are eating too much meat and carbs (potato, sweet potato, corn, pasta, rice or bread) with their meals and not enough low carb vegies. Adults need 5 serves of vegetables or salad a day.  Low carb vegies give us next to no carbs or calories but plenty of vitamins, minerals and fibre.
One serve of vegetables= 1/2 cup of cooked vegies. The pictures below show 1 serve of each vegetable, with the carbs at the top of the picture (corn and mashed potato) and the low carb vegies below.

Below are three meals. They include 3 serves of low carb vegies, 1 serve of carbohydrate (pasta, mash or corn) and 1 serve of meat or chicken using a Portion Perfection plate.