It’s amazing how divisive the carbohydrate versus fat debate has become. I used to think chefs were a tricky bunch. Jeeze! They are nothing when you read the fights breaking out amongst cancer researchers, scientists and biochemists. Not to mention engineers, MD’s (medical doctors), RD’s (registered dieticians) and nutritionists. There’s a whole pile of voices to be heard. Talk about attacking each other’s work!
I think one of the sad things is that when it’s suggested that there may be better diets for cancer patients to undertake – other than the standard food pyramid/high carb, low-fat approach – some folks assume you are suggesting that diets can cure cancer. There seems to be a serious lack of comprehension about what is being suggested by cancer researchers, doctors and oncologists interested in recent nutritional developments.
To be clear, and for the record, do I think diets can cure cancer? Absolutely not. Do I think certain promises of certain dietary approaches are bogus? Absolutely.
But back to nutrition and cancer. Lots of the criticisms relating to LCHF and Ketogenic diets are that they are “fad” diets. Unfortunately, I don’t think you can call a Ketogenic diet – used to treat epilepsy for over 100 years, for instance – a fad.
Fad for cancer? Well, I completely accept most of the evidence to date has been preliminary and although it’s certainly compelling, yes; it’s mainly based on animal studies and small case studies. Do I think positive results in mice experiments guarantee success in humans? No. But we’re talking a diet here. Not a cytotoxic drug. And once it’s been shown to be safe – even for Stage 4 & terminal cancer patients – and the biochemistry makes sense, then isn’t it worth considering as an adjunct (meaning in addition to conventional treatment)?
If you read through the ESPEN guidelines to cancer Nutrition
You’ll see that one of the things they point out is this:
“…Metabolic derangements like obesity and insulin resistance are associated with increased risks of cancer recurrence [, ].”
Insulin seems to be a bit of a smoking gun. Same for obesity. Some folks say “sugar feeds cancer” which is an oversimplification of a complex process. People who disagree with this statement often do so on the basis that all cells require glucose. We agree that even if you do not eat one gram of carbohydrate, your liver will still produce enough glucose (out of amino acids or glycerol, for instance) to feed certain parts of the body that can only run on glucose. What they often leave out is this: most tumours are highly glycolytic – i.e. they prefer glucose as their main source of energy. But cancer cells will also find fuel in glutamine and other proteins. But they do find it harder to metabolize fat, unlike your normal healthy cells. Inevitably they will eventually find a way to metabolize fat… and some tumours display that capability from the get-go, but bottom line is that most tumours do like glucose. You’ll never eliminate all glucose from your system. But you can certainly prohibit the amount you make available. And that just seems like common sense!
This recent presentation by professor Dawn Lemanne, who is a medical oncologist, is really worth looking at. She discussed different diets, for different cancers as well as fasting and effects of combining targeted diets with conventional treatment:
The idea of reducing carbohydrates does not mean that I think we should screech, “Sugar feeds cancer” when I see someone eating cake. But my own view of the emerging evidence is that overeating carbs is a problem for cancer patients. And the food pyramid is full of too many carbohydrates. Especially processed ones like bread and pasta, baked beans, fruit juice but also fruits like bananas.
I just think there are better things to eat that will help keep my blood glucose low, and therefore stop huge rushes of insulin, which may act as a growth factor for cancer cells.
I have had cancer twice. I believe in keeping my system “cool” in relation to inflammation and insulin. I have a BMI of around 22…which could be even leaner (but I’m a greedy-cow chef and run lots of restaurants and cafes, so my entire working life revolves around food!!!) But I don’t think you have to be a genius to work it out. I wish people would stop embarrassing themselves by accusing highly regarded oncologists, researchers, scientists of being snake oil sales people, by simply suggesting that high carb foods are most likely not beneficial (to put it mildly!) for cancer patients.
But maybe we just need to change the conversation a little bit. Or at least look at the concerns of both sides of this divide: I hear people demanding evidence, of the evidence, for low-carb or KD’s in relation to cancer. This implies that the current guidelines to cancer nutrition are based on…strong scientific evidence. Worryingly, this does not seem the case. This was a recent publication of cancer nutrition guidelines by ESPEN.
“We searched for the best evidence….The randomized controlled trials included in the systematic reviews were often of medium or low quality, with small sample size, often with no calculation of sample size, and with poor or unreported allocation concealment. Thus, for many cells in the matrix of the clinical questions, we found no evidence or only low quality evidence, and, in these cases, it was necessary to base our recommendations on our expert opinion. “
Holy moly! They are saying that for many of the recommendations – upon which current guidelines are based – have only low quality or no evidence to back them up.
This implies there is a real lack of evidence for current guidelines. So maybe, opposing sides should consider, how much evidence do they need to make changes to policy? Ironically, it looks as though many of the on-going studies for Ketogenic and low carb diets in relation to cancer, may soon become some of the strongest pieces of evidence available upon which guidelines should move towards.
This study came out after the ESPEN guidelines were published:
It shows that the MAD diet (which is a modified version of Atkins and not straightforward KD that’s used in epilepsy and does not include enough protein that’s required for non-epileptics) is safe and feasible for even advanced cancer patients. The diet was also well tolerated. One of the criticisms of the KD in the ESPEN report is that it’s unpalatable and therefore hard to maintain. I think the current wave of interest including publication of cookbooks and release of videos showing how to create delicious KD friendly recipes means that it’s no longer valid to say that the KD is unpalatable.
So, although I fully understand why “sugar feeds cancer” can raise hackles, maybe we can just change the conversation to suggest that reducing insulin is simply good practice for cancer patients? There are bidirectional links and risk factors for cancer & diabetes, hyperinsulinemia, hyperglycaemia and a high glycaemic load – they are all associated with increased risk of cancer. Studies clearly show that these conditions are also associated with poorer prognosis in cancer patients.
Now, look back at the food pyramid: do you think one supports the other?
When I was diagnosed with breast cancer in 2013 the succinct nutritional advice I was given by my brilliant team in St Vincent’s hospital was not to gain weight and that previous concerns about eating fat were no longer valid. I was not at risk of cachexia and therefore was never going to see a dietician. But those two comments led me to start reading about weight gain, the foods most likely to cause weight gain and the impact that would have on my recovery. That led me to published papers about carbohydrate restriction and benefits of exercise. I pieced together what simply made sense to me at the time. Get off my backside. Move more. Keep blood sugars low. And stop eating my most favourite foods that were going to cause blood sugar spikes and release of insulin, which we know is not great for cancer. That’s all. And it’s what I am an advocate for in relation to my diet as a cancer patient.
Did I follow a Ketogenic diet? No, I followed a low carb, healthy-fat diet.
It was a bit of a no-brainer, for me.
However, I don’t think that my diet was remotely as much of a force on my tumours as my 6 rounds of chemo, my mastectomy, my 6 weeks of radiation and four bouts of surgery. But do I think it was a better approach than a food pyramid? Absolutely!!! Do I think I supported my system throughout this ordeal through my diet and exercise? Without a doubt.
During my year of treatment, I used to watch Dr Craig Thompsons lectures to students in Memorial Sloan Kettering and one of his best lectures (for a cancer patient to watch) is this one:
“It matters where your calories come from” and he goes on to say that if you over-feed people with carbohydrates, you dramatically increase their risk of cancer.
But if you overfeed them, with fat, then you don’t increase their risk at all.
So then, why do we still see some institutions and cancer charities recommend food pyramids on their websites that vilify fat? Despite the changes made to the latest version of the food pyramid – where fruit and vegetables take prominence over the bread, cereal, pasta and wholegrain – the fact remains that a high-carb, low fat diet is still being promoted.
Sadly, it seems to me – as a cancer patient – that the disconnect between published evidence and clinical practice persists. In summary, I think this advice from UK Oncologist Prof Rob Thomas sums it up nicely:
Prof Rob Thomas:
“If you have lots of foods that increase your glycaemic index (sugar, processed carbs or even overeating), then you have an increased risk of cancer. So how much evidence do you actually want. We’ve got laboratory data, we’ve got an underlying very feasible biochemical pathway which directly shows the link to cancer progression, we have large cohorts, too…. People want advice based on common sense. If some health professionals say, “I’m going to wait for the randomised placebo controlled trials on sugar to advise my clients”- first of all, this is never going to happen. And you have to draw a line in the sand somewhere with the level of data.”
And here’s my version of how I sum the whole debate up:
“Calm the f*ck down! If you like eating a high carb diet and not exercising, then fine. If you are interested in nutrition, then start reading and reviewing the science for yourself. See what suits you and remember that your diet should support your treatment. I believe in the power of staying positive. And the fights that break out are all so pointless, to be honest. Eat what you want. But I know what I want to eat and am happy and proud to share that info with folks that are interested”