To manage food costs, it was also important to make a shopping list and to stick to it, Ms Blackmore said.
"Don't be tempted by specials that you don't need or won't use. Remember it's not a special if you don't need it or won't use it.
"One of the most expensive items on you dinner plate is the protein - fish, meat or chicken - and we frequently hear that we eat too much of it. As a guide 500g boneless meat, fish or chicken will feed four people."
To keep costs down when feeding teenagers and men who undertook physical work, meals could be "bulked up" with beans, lentils and vegetables, which were all cheap, Ms Blackmore said.
Planning the week's meals in advance would also avoid the quick-fix of getting expensive takeaways.
"This might sound boring, but not only does meal planning save money, but it also saves time."
Ms Blackmore recommended learning how to cook a Bolognese-style mince sauce, which could create a large variety of meal options including pastas, pizzas, tacos and sloppy joes.
She recommended putting a freezer to good use by buying meat on special and freezing it for later.
More food tips could be found on Ms Blackmore's blog at rachelskitchennz.com.