What happens when the body is asked to fight cancer but cannot get enough fuel? New cancer nutrition guidance from Vietnam’s Ministry of Health puts that question at the center of care, not at the edge of it.
The guidance says nutrition should begin at diagnosis, continue through treatment, and be adjusted for each patient. It also sends a clear warning that low-calorie diets, including keto, should not be used as a cancer treatment shortcut because they may raise the risk of malnutrition.
Food becomes part of treatment
The new document was issued under Decision 1768 and is designed for health facilities caring for adults with cancer. The PDF lists Deputy Health Minister Tran Van Thuan and Ha Anh Duc in the steering group, with Duong Huy Luong, Truong Tuyet Mai, and Nguyen Trong Khoa named as lead editors.
Its message is simple: Cancer care is not only surgery, chemotherapy, radiation, or newer drug treatments. What lands on the tray can affect strength, recovery, and whether a patient can keep going through treatment.
The numbers for patients
For American readers, the main daily target works out to about 11 to 14 calories per pound of body weight. For a 150-lb. person, that means roughly 1,700 to 2,050 calories a day, though doctors may adjust the number if the patient has swelling, obesity, or rapid weight loss.
Protein gets special attention. The guidance calls for at least 0.54 grams of protein per pound of body weight each day, rising to about 0.68 grams per pound in people with severe malnutrition, major muscle loss, or severe wasting.
For a 150-lb. person, that means at least 82 grams a day, and sometimes more under medical supervision.
Fat should stay below 30% of total daily energy, with a preference for unsaturated fats and limits on saturated and trans fats. Vitamins and minerals should generally match normal daily needs. Higher doses are reserved for proven deficiencies and should be supervised by health professionals.
Why weight loss matters
Cancer and nutrition have a two-way relationship. Tumors and treatments can cause poor appetite, nausea, mouth sores, diarrhea, taste changes, and higher energy needs. Then poor nutrition can weaken the body’s response to treatment.
The guidance says malnutrition in cancer patients can reach up to 80%, depending on cancer type, stage, and treatment method. The risk is especially common in cancers of the digestive tract, liver, bile ducts, pancreas, head, and neck. A few pounds lost quietly at home can become a clinical problem fast.
The keto warning
The keto diet is a very low-carbohydrate eating plan that pushes the body to use fat as a major fuel source. It gets plenty of attention online, but the ministry says low-energy diets, including keto, are not recommended for cancer patients.
Why the warning? The guidance says there is not enough scientific evidence that these diets improve cancer treatment results. On the other hand, they can make it harder for patients to get enough calories, protein, and micronutrients, especially when the immune system is already under stress.
European clinical nutrition guidance reaches a similar practical point.
The European Society for Clinical Nutrition and Metabolism recommends screening nutrition from diagnosis, using roughly the same energy range, prioritizing protein, and avoiding energy-restrictive diets in patients who are malnourished or at risk.
Screening starts early
The new guidance calls for malnutrition risk screening as soon as cancer is diagnosed. That means checking more than weight alone. Teams are asked to look at body mass index, a weight-for-height measure, recent weight loss, muscle mass, food intake, and relevant clinical indicators.
In practical terms, a patient who still looks “normal” may still need support. The first step is usually food by mouth, with counseling and nutrient-dense meals.
If that is not enough, oral nutrition supplements, tube feeding, or nutrition through a vein may be considered depending on the gut, the treatment plan, and the patient’s condition.
A wider cancer burden
The timing matters because cancer remains one of the world’s biggest health threats. The World Health Organization’s cancer research agency estimated about 20 million new cancer cases and 9.7 million cancer deaths worldwide in 2022.
It also warned that aging populations and lifestyle risk factors will keep pushing the burden higher.
That’s why these guidelines are less about a “cancer diet” and more about a care system. They ask hospitals to catch malnutrition early, personalize support, and bring treating doctors and nutrition specialists into the same conversation. For many patients, it could make treatment a little more tolerable.
The official guidance has been published by Vietnam’s Ministry of Health.
