Ready-made chicken tikka masalas may look the same but they can vary greatly in their fat and salt content, warns the Consumers' Association.
There was wide variation in salt and fat content between products
It found huge variations between different versions of the curry and four other ready-meals sold in 10 leading UK supermarkets.
Some products contained three times the fat per 100g and up to nine times the amount of salt of their rivals.
The association says shoppers should take care over which meals they buy.
The five types of food looked at were cheese and tomato pizza, chicken tikka masala, steak and kidney pie, quiche Lorraine and beef lasagne.
RECOMMENDED DAILY AMOUNTS
Fat - 95g for men, 70g for women
Saturated fat - 30g for men, 20g for women
Sodium - 2.5g for men, 2g for women
Fibre - 20g for men, 16g for women
Sugar - 70g for men, 50g for women
The difference in salt and fat content between rival products was large.
For example, the Real Italian Stonebaked Microwaveable Margherita Pizza from the Little Big Food Company contained nine times the amount of salt of the Little Big Food Company Organic Stonebaked Pizza Margherita.
Similarly, Marks and Spencer's Lasagne Al Forno contained three-and-a-half times more fat than Somerfield Lasagne.
Some ready meals contained worrying levels of salt or fat in a single portion.
One of the chicken tikka masalas tested contained 47.3g of fat, which is over two thirds of the recommended daily amount for women and over half of the amount recommended for men.
A lasagne contained 3g of sodium per portion (multiple by 2.5 to get the salt level), which is more than a day's recommended amount for men and women.
Mr Nick Stace of the Consumers' Association said he would like to see manufacturers reduce levels of fats and salt in their products.
"Reducing levels of salt and fat shouldn't mean that we have to eat tasteless, bland food.
"Some of the premium ranges were lower in fat and salt than the standard versions proving that manufacturers can produce tasty ready made food with less salt and fat," he said.
He said clearer food labelling would help people make informed choices about the food they eat.
The Consumers' Association believes labels should take into account how much of the product is actually eaten rather the current method that bases it on 100g of the product.
It also backed last week's recommendation by the Commons health committee that food labelled under a 'traffic light' system, warning people which foods are high in sugar and fat
A spokeswoman from the British Nutrition Foundation said manufacturers were working to reduce salt levels in processed food.
She agreed that food needs to be clearly labelled, but was not sure whether the traffic light system would be the best approach.
"There's no scientific evidence to back it up. We need to investigate it further," she said.
Mr Kevin Hawkins, Director General of the British Retail Consortium is against the traffic light approach.
He says it would lead to artificial segregation of foods by attacking staples of our diet such as meat and dairy products.
A spokesperson from the Little Big Food Company said their Organic Stonebaked Pizza was cited as the pizza with the lowest salt content in the study.
He said their microwavable pizza with the higher salt content was a different product, aimed at being a snack.
"Relative to other snack products it's a relatively good product in terms of salt content."
He agreed with the Consumer Associations' principles and said: "We are bringing down salt content across all our products and will continue to do so."
A spokeswoman from Marks and Spencer said they offer customers "wholesome, healthy and quality food" which is clearly labelled to allow them to make informed choice about what they buy.