Several popular liquid breakfast products including Sanitarium's Up & Go and Kellogg's breakfast drinks make dodgy nutritional claims, consumer group Choice says.

Choice says an investigation into 23 liquid breakfast products including Devondale Fast Start, Dairy Farmers Oats Express and Aldi Goldenvale Quick Start has found they make false claims about being high in fibre or a good source of protein.

"Shonky" claims: Sanitarium's Up & Go was one of the products criticised by Choice.

"Shonky claims on liquid breakfasts such as 'high in fibre', 'fibre for digestive health', and 'goodness of three grains' is a cause for concern," Choice spokesman Tom Godfrey said.

"Liquid breakfasts have on average 1.5% fibre, which is well below the 10 per cent benchmark for high fibre.