Diets Debunked

Apple Cider Vinegar. No longer just a delicious base for a salad dressing, but the title of one of Netflix’s most successful series of 2025 so far. A series, which, focuses on the dark underbelly of alternative medicine, and the people who push it for money.

The star of the show, is of course, Belle Gibson, famed across the world for her lies about having cancer which fuelled a money-making scheme, netting her over a million Australian dollars and making her the face of the wellness and natural medicine scene of the time.

But we aren’t here to talk about Belle.

Instead, I want to talk about the other insidious undercurrent of the series, one which has been taking place for decades at this point. A treatment which preys on the vulnerable, offering them hope with talks of healing and health which conventional medicine may not be able to give them with their poor prognosis. I am of course, talking about Hirsch Therapy.

Except it isn’t known as Hirsch Therapy in real life. Instead, it is widely known as Gerson Therapy.

What is Gerson Therapy?

The belief behind Gerson Therapy is that proper diet and significant lifestyle changes can restore the body’s ability to heal itself, by tackling the root causes of disease (which they believe are toxicity and nutritional deficiency). Consuming copious amounts of vitamins and minerals in specific forms, alongside digestive enzymes, will, according to the Gerson Institutes website, do the following:

“These substances then break down diseased tissue in the body, while coffee enemas aid in eliminating toxins from the liver. Oxygenation is usually more than doubled, as oxygen deficiency in the blood contributes to many degenerative diseases. The metabolism is also stimulated through the addition of thyroid, potassium and other supplements, and by avoiding heavy animal fats, excess protein, sodium and other toxins.”

– The Gerson Institute Website, accessed 19th February 2025

The therapy involves 4 pillars that it accredits to its success:

• Diet: A diet which is plant-based and organic, focusing on fruits, vegetables and wholegrains, in both raw and cooked formats. Examples of meals would include their Hippocrates soup (which is a soup made from celery, onions, leeks, tomatoes, potatoes and parsley), salads, cooked veggies and potatoes.
• Juices: Perhaps the most identifying part of the Gerson Therapy diet (apart from those coffee enemas!), Gerson Therapy recommends the consumption of multiple glasses of juice (carrot, carrot-apple and green juices) per day. The idea is that you can drink the equivalent of 15lbs of produce per day, which is far easier than trying to eat it. What is interesting is that the juices must be prepared in a specific way- using a two-step or masticating juices with a separate hydraulic press. A normal juicer would not be considered on protocol.
• Detoxification: The use of coffee enemas (alongside castor oil) is rigorous on Gerson Therapy, with the idea that the coffee helps in “assisting the liver in eliminating toxic residues from the body”. The amount you do depends on the number of juices you have to drink, as prescribed by the Gerson practitioners. There are also reports of the use of ozone enemas, as well as hydrogen peroxide enemas, however this is not mentioned on their website.
• Supplements: There are a significant number of supplements prescribed on Gerson, including potassium compound (3 types of potassium compounds in one), Lugol’s solution, thyroid hormone, pancreatic enzymes and niacin.

What does the Gerson Institute claim that Gerson Therapy can do?

Effectively, the Gerson Institute claims that, if you follow the protocol properly, you can cure your cancer.

To give them credit, they do have a page where the list various types of cancer and do specify that certain cancers (such as bladder, thyroid etc) have seen very limited success in Gerson treatment, and occasionally, advise against the use of Gerson therapy. This being said, they do still claim that various types of cancer such as ovarian, breast, lung and colon cancer have seen many successful recoveries, and so we can’t exactly let them off the hook here. Cancer is seemingly the most common reason for people to begin Gerson Therapy, and their blog is filled with various testimonials (which are very convincing by the way) from previous patients who have successfully “cured” their cancer with Gerson.

It isn’t just cancers they claim to heal, however. Conditions such as Rheumatoid Arthritis, lupus, diabetes and high blood pressure, are also considered treatable using Gerson.

What’s the evidence for all of this?

Judging by their website, you’d be forgiven for thinking that there was a good evidence base behind their claims. After all, they don’t recommend the therapy to everyone, they have dozens of very heartfelt and emotional testimonials from previous patients, and the website has some great medical jargon, so surely there is some scientific evidence to back up their claims somewhere?

Unfortunately, that isn’t quite the case.

As of 2025, there have been no randomised-controlled trials on the therapy. This is partly because the ethical implications of trialling Gerson on an RCT basis would be severe and would not be approved by any independent scientific researchers. We also do not have any observational studies suggesting a link between Gerson Therapy and healing conditions such as cancer. We don’t even have any animal studies investigating the link between Gerson and cancer remission.

The only evidence we have that Gerson works are the reports that Max Gerson and the Gerson Institute themselves have published. These include a book with 50 case studies, as well as anecdotal evidence backed up by testimonials on the website. Investigations into these claims by various Cancer Institutes have found that there was no evidence to back up the claims that the individual was in remission or had been cured by the therapy, and for those which there was evidence of remission, the individual had been undertaking conventional treatment at the same time (such as chemotherapy, radiotherapy or cancer excision).

The other issue with the strength of this evidence is the fact that all this data focuses only on survivors of the therapy. The Gerson Institute does not make public the number of people who did not survive 5 years, 2 years, 1 year, or hell, even 6 months after completing the therapy. Having statistics to compare survivors to non-survivors would be very useful in identifying the efficacy of the therapy, but no such statistics have ever been published. Equally, having statistics on how many completed Gerson as a complimentary therapy (alongside conventional/modern medicine) vs those who completed it as an alternative therapy (with no other medical intervention) and their survival rates and remission rates, would also be very helpful.

But of course, the Gerson Institute won’t publish these. I wonder why.

The dangers of Gerson Therapy

As a dietitian, I am constantly worried about the dangers that Gerson Therapy may be putting patients under when it comes to cancer recovery and complications. Generally, I have 4 main concerns:

• Encouraging Gerson as an alternative therapy and not a complimentary one.

Whilst it is not explicitly stated that you should not continue with modern medical treatments of cancer when undertaking Gerson Therapy, there is a general distrust of modern medicine within the alternative medicine space, which may encourage individuals to shun conventional treatment to undergo Gerson Therapy. This is concerning to me, particularly in cancer cases which are treatable when treatment begins early enough. I worry that people may choose Gerson over these conventional medical interventions, and when they decide to eventually trial conventional medicine, it will be too late.

This concern isn’t completely unfounded either. I have seen the case of a patient personally in the course of my work who had a treatable cancer in the past, who chose alternative medicine instead of the operation and radiotherapy which was offered. They would have had a good chance of survival as the cancer was caught early. Unfortunately, they decided against the medical advice and chose Gerson Therapy instead, which did not work. They then decided that they wished to trial conventional treatment again, but at that point, it was too late. They died a few months later, leaving behind a young family.

• Electrolyte disturbances

Gerson therapy is not only a very low sodium diet but also promotes the use of multiple enemas a day in order to “detoxify” the body. Not only is there no evidence that coffee enemas detoxify the body, but the use of enemas has been associated with a further reduction in blood sodium. The combination of both of these has meant that numerous people have been hospitalised whilst undertaking the Gerson Diet due to hyponatremia (low sodium levels in the blood). Hyponatraemia can be very serious; as sodium is an osmotic solute, it will always try to maintain a balance across tissues. If you have low sodium levels in your blood, your body will pull water into your tissues to keep that blood level of sodium higher. One of the tissues it can pull water into is the brain; in severe cases of hyponatraemia, brain swelling and subsequent damage can occur.

As far as I can tell, there is no reported case of Gerson-induce hyponatraemia going this far. However, it is a distinct possibility and should be considered a danger of the therapy.

• Lack of protein and calories and impact on morbidity and mortality.

As a dietitian, perhaps the most concerning danger of Gerson is the avoidance of higher calorie, higher protein foods in those with active, acute disease. Ultimately, study after study has concluded that those with cancer or other active diseases which can impact diet and nutrition have a lower risk of death and complications from the cancer when they maintain their body weight. Consuming a diet which is low in calorie, high in volume, and low in protein, no matter how many micronutrients it contains, is associated with a higher risk of malnutrition, a higher risk of complications, and a higher risk of death from the disease.

• Impaired colonic function and potential morbidity impacts.

Enemas are not recommended unless absolutely necessary for a reason. Using enemas regularly, let alone multiple times a day for months at a time, can weaken the colons’ function, causing worsened constipation, colitis and bleeding. If done incorrectly, perforation of the bowel can occur, along with infections and other severe complications.

It’s not just the impacts on your physical health that make Gerson dangerous

Ultimately, what the Gerson Institute is selling you is the hope that you can cure your cancer with diet and natural alternatives to conventional cancer treatments. This hope is a powerful thing; it makes people feel empowered and positive in a very sad and scary situation.

Gerson is a protocol which requires unwavering dedication and perfect adherence in order to be successful according to its promotors. Unfortunately, though, due to it’s complexity, it’s cost, and it’s time commitment, it is incredibly difficult for most people to follow it perfectly.

This means that, if the therapy doesn’t work, many patients feel guilt, shame and like they have failed as their adherence wasn’t as stringent as it is required to be.

This seems to wash responsibility of cancer progression, reoccurrence or death from the Gerson Institutes hands, as they will always be able to fall back on the fact that the person mustn’t have followed the protocol properly. This allows them to escape culpability of selling a protocol which doesn’t cure cancer, and instead laud the few people who have seen a cancer remission when taking their protocol, whether they followed it properly or otherwise.

Diet absolutely can influence your risk of developing cancer, and dietary intake can also significantly impact your likelihood of survival. However, the dietary patterns associated with these outcomes are not what the Gerson Institute promote. Instead, they are promoting a non-scientifically backed, juice-based hope protocol, which has no evidence behind its claims other than the anecdotal evidence the clinic publishes themselves.

If you are thinking of trialling Gerson Therapy, I understand. You want to avoid the awful symptoms and side effects of chemo and radiotherapy. You want to avoid surgeries which can have their own negative impacts, both physically and mentally. You want to heal yourself naturally.

But the reality is, there isn’t the evidence to suggest that Gerson Therapy can provide this for you. What there is evidence for, however, is modern medicine and treatments, treatments which are scientifically backed and ever evolving to give you a better chance of survival. Don’t turn your back on these for the hope that alternative medicine gives you. If you must, do those alternative therapies alongside modern medicine, not instead of. Please don’t become another statistic of survival rates in untreated cancers.