Food is not medicine, anyone claiming it is medicine is selling you something, like a diet plan, but nutrients can impact cancer cells.

How that applies consistently is unknown so a new tool hopes to create an exploratory method using mice. Mice don't translate well to humans, they are not little people, but they can exclude effects in humans and that has value also. 

Metabolism is an overused word but it is not a thing, it instead refers to the set of processes that allow an organism to use nutrients from its environment in order to function. There are a lot of moving biological parts and relative amounts of sugars, fats and protein in the diet determine what “fuel” is available for the cells, and also how those cells process the nutrients. Cancer cells, like other diseased cells, change their metabolism to support survival and growth.

A research team at King’s College London created a map of all metabolic pathways in the mouse. They put experimental data into a simulator by measuring the levels of gene expression in liver and liver tumors from mice that had been fed either ‘healthy’ diets or ‘unhealthy’ diets, rich in fats and sugars. 

They found specific changes in metabolism associated with unhealthy diets, which were seen to promote the production of glycerol and succinate in both cancerous and healthy tissues. They also observed that the differences in metabolism between healthy and cancerous cells were highest in the context of an unhealthy diet, suggesting that tumors are able to better exploit unhealthy diets to promote survival and growth.

To try and get clearer answers, they simulated the effects of a change in dietary components - from healthy to unhealthy, and unhealthy to healthy - in various combinations. They decided that, although some cancer-specific metabolic functions persisted on healthy diets, they could also reverse many of them, but only when both fats and carbohydrates were limited.

It's exploratory but there are confounders. It's a computer simulation and in mice. Diets heavy in calories lead to obesity and general poor health, which is a contributor to cancers and liver disease and type 2 diabetes. The authors hope their work spurs more conclusive findings that may one day have human relevance.