Plant-based or Keto: Which Is Optimal for Health, Reduced Cancer Risk in Survivorship?

Cancer specialists at Memorial Sloan Kettering (MSK) Cancer Center evaluated the relationship between diet and cancer.¹ Evidence that reducing weight is helpful for lowering cancer risk is growing, particularly for people who are obese and older, explained Neil M. Iyengar, MD. But what diet is best for lowering cancer risk and achieving weight loss?¹

MSK cancer researchers receive many inquiries from patients regarding which type of diet is best for restoring their health after having been treated for cancer and for lowering the risk of developing additional cancers. Should they try a whole food plant-based diet (WFPBD) or a ketogenic diet (keto)? There is no one solution for all, as the researchers note that both diets help patients achieve weight loss. However, the data concerning which diet reduces the risk of cancer are not as clear, although WFPBD may be more effective than keto at reducing risk after a cancer diagnosis.²

Comparing Keto With WFPBD

Dr Iyengar and his colleague, Urvi Shah, MD, focused on 2 popular diets: the keto diet and a WFPBD. The 2 diets have subtle but significant differences.

The aim of the keto diet plan is to metabolize ketone bodies instead of the sugar that comes from eating carbohydrates. Ketones come from fatty acids, which are prevalent in high-fat foods such as meat, dairy, fish, oils, eggs, nuts, and seeds, as well as low-starch vegetables. Ideally, the keto dieter consumes fewer than 40 g of carbohydrates a day.

By contrast, the plant-based diet requires that 80% to 90% of foods should be whole and unprocessed foods such as fruits, vegetables, whole grains, legumes, nuts, and seeds. The plant-based dieter usually reduces carbohydrates to less than 26% calories consumed, or fewer than 100 to 130 g per day. An advantage to this diet is that whole grains have been associated with a reduced risk of cancer.^1,2 There may be some minimal crossover with both diets, but the amount should be less than 10% and not on a regular basis.

The American Institute of Cancer Research (AICR)/World Cancer Research Fund (WCRF) and the American Cancer Society (ACS) recommend following a diet that incorporates primarily plant-based foods. This diet also limits sugary beverages, highly processed foods, refined carbohydrates, and processed and red meats. It advocates eating foods that are high in fiber and low in calories, leading to a feeling of fullness shortly after eating so the patient consumes fewer calories. The keto diet’s protein rich foods can suppress appetite, thereby also leading to the patient eating less. Thus, both diets reduce calorie intake.¹