The predilection of cancer cells for sugar was already appreciated by Ernst Freund, one of the first modern cancer researchers, in 1885. This first finding explains the diagnostic test in most solid tumors is the FDG-PET scanner, which detects the increased metabolism of glucose in cells. 
In the early decades of the 20th century, pioneers like Otto Warburg and Alexander Braunstein were already establishing a strong relationship between nutrients and diseased cells. Their research led to the development of new approaches to the treatment of various illnesses. Of course, it was also determined that cancer had a strong nutritional base, among its myriad of causes.
The nuanced work of these and other scientists leads us to the question of how much fat and what type should provide a diet for preventive or therapeutic purposes. To find out, the key is in the differences between healthy and diseased cells.
Healthy cells can obtain the energy they need from glucose, fat or protein. In contrast, cancer cells are only efficient at transforming glucose and can barely get energy from proteins and even less from fats.
This reality at the metabolic level is reflected in the relationship that exists between the incidence of cancer and diets rich in carbohydrates and total calories that lead to the elevation of LDL cholesterol, triglycerides, insulin — a major inducer of cell proliferation — and blood sugar.
Researchers again turn their attention to the metabolism of diseased cells, their hunger for sugar, and the acidic environment they create to reproduce better.
And a diet that practically eliminates sugar (carbohydrates) as an energy source in favor of fat is considered a preventive and therapeutic strategy. 
According to human biology doctor Ulrike Kammerer, a researcher at the Julius Maximilians University of Würzburg (Germany) and co-author of Ketogenic Nutrition Against Cancer, the most appropriate food may be that of our farthest ancestors.
The hunter-fisher-gatherer peoples fed on what they hunted and fished and, therefore, obtained the energy of proteins and fats.
An example is the Innuits, the inhabitants of the Arctic Circle, who ate very fatty meats and fish, and who knew practically no cancer or cardiovascular diseases, as the European explorers proved.
Or the inhabitants of the Tokelau Islands, in Polynesia, whose main source of energy was the coconut, rich in fat, and who enjoyed great health until they began to consume the flour-based products that the Europeans brought.
Despite the obvious relationship between blood sugar rates and cancer, the official recommendation continues that carbohydrates contribute between 60 and 70% of daily calories (we inherit a culture based on grain reserves).
The advice is maintained even for cancer patients and they are only recommended to increase the proportion of fat and protein when they suffer weight loss and muscle mass, due to the progression of the disease.
Scientists who are supporters of the so-called “ketogenic diet” recommend replacing carbohydrates with fats. Natural foods rich in fats are metabolized without difficulty; they do not raise the sugar and reduce the chances that the genes related to cancer are activated. 
With a diet that includes them as the main energy ingredients, we can create an ecosystem in the body to reinforce the healthy parts, without benefiting the cancer cells, and even inhibiting them.
At Verita Life our in-house nutritionists, also personally design menus to suit each patient individually and their nutritional needs specifically.
1 Nutr Metab (Lond). 2011; 8: 75. Published online 2011 Oct 26. doi: 10.1186/1743-7075-8-75 PMCID: PMC3267662 PMID: 22029671 Is there a role for carbohydrate restriction in the treatment and prevention of cancer? Rainer J. Klement and Ulrike Kämmerer
2 Aging (Albany NY). 2018 Feb; 10(2): 164–165. Published online 2018 Feb 11. doi: 10.18632/aging.101382 PMCID: PMC5842847 PMID: 29443693 Ketogenic Diet in cancer therapy. Daniela D. Weber,1 Sepideh Aminazdeh-Gohari and Barbara Kofler
3 Medical News Today What to know about low-carb, high-fat diets. By Jenna Fletche Reviewed by Natalie Olsen, RD, LD, ACSM EP-C