Keto and the Danger of Fad Diets

Former American President Benjamin Franklin famously stated that:

In this world, nothing is certain but death and taxes.

We could safely add ‘…and the proliferation of fad diets’ to this quote!

As long as we have a problem with overweight and obesity, we’ll have an abundance of fad diets. This is certainly the case in Aotearoa New Zealand.

Currently, the Ketogenic Diet (Keto) appears to be one of, if not the most popular of these fads.

Whitcoulls and Paper Plus are awash with Keto books and magazines full of Keto articles. Supermarkets and health food/supplement stores stock a range of Keto products. Celebrities sing the praises of Keto.

And if you’re like me, your junk email folder is probably full of promotions for ‘Keto gummies’.

But is Keto really a fad or is it actually a legitimate diet?

According to Dietitians Australia, fad diets are identifiable by:

• The banning or demonising of certain foods/food groups.
• Promising quick, easy weight loss with little effort.
• Ignoring national dietary guidelines and even blaming such guidelines for health and weight problems.
• Highlighting a certain food or food group as key to the diet’s success.
• Using the endorsements of celebrities or celebrity doctors as evidence of the diet’s success, rather than scientific evidence.
• Recommending the same diet formula for everyone, without accounting for individual needs.

Keep these points in mind as you read through this article where we’ll examine:

• What Keto is and how it works.
• Whether the evidence supports or refutes Keto.
• LDL cholesterol – what it is and why its important.
• What the ultimate dangers of fad diets are.

What is Keto and how does it work?

‘Keto’ is one of the popular diets we analyse in our Personal Trainer and Weight Management Coaching programmes.

Fundamentally, Keto is a low-carbohydrate, high-fat eating plan. Recently, it has gained popularity as a weight-loss solution on the back of the low-carb diet craze. Starting in the 1970s, this craze includes the Atkins, Zone, Paleo, South Beach and Dukan diets.

What distinguishes Keto is that it is exceptionally low-carb and high-fat.

While there are a variety of Keto diet plans, they all generally require that:

• 70-80% of all calories come from fat.
• 5-10% of all calories come carbohydrate.
• 10-20% of calories come from protein.

Regarding quantity, Keto typically requires that total carbohydrate intake be reduced to less than 50 grams per day. With some Keto variants, this falls to as low as 20g/day.

To provide context, one banana provides approximately 23g of carbohydrate and one slice of bread typically provides 13-17g.

To achieve such low-carbohydrate intakes, Keto essentially ‘bans’ all carbohydrate-rich foods.

This includes breads and cereals, pasta, rice, potatoes and other starchy vegetables, legumes, most fruits and fruit juices.

To achieve the required high-fat intakes, Keto promotes the consumption of foods high in:

• Saturated fats such as meat, poultry, and processed products such as salami, lard and butter.
• Unsaturated fats such as nuts, seeds, avocados, plant oils and oily fish.

The objective of Keto is to induce a metabolic state of ketosis.

In the absence of the body’s preferred energy source, glucose, which is obtained by eating carbohydrate-rich foods, the liver produces ketone bodies from its reserves of body fat. In the absence of glucose, ketone bodies become the body’s primary energy source.

Ketosis is a metabolic state where the body predominantly burns fat for energy instead of glucose.

While it seems logical that this would help us to lose weight (fat in particular), what does the evidence say?

Does evidence support Keto?

While Keto has become popular for weight loss, low-carb high-fat eating plans actually have a considerable history. ‘Keto-like’ diets:

• Have been used to help control diabetes from as early as the 19th century.
• Were introduced as a treatment for epilepsy in children resistant to medication in the 1920s.
• Have been tested and used in closely monitored clinical settings for cancer, diabetes, polycystic ovary syndrome and Alzheimer’s.

A body of research exists that supports Keto or Keto-like diets for such conditions…when applied in clinical settings.

In non-clinical settings however, the evidence supporting Keto as a weight loss diet is somewhat ‘conditional’.

In one study [ref 1], 39 adults with obesity were placed on a Keto diet for eight weeks. The participants:

• Lost 13% of their starting bodyweight – a lot of weight in a short period of time!
• Experienced significant reductions in waist and hip girths, bodyfat, and blood pressure.

However, two weeks after the diet finished, participants ghrelin levels and their ‘urge to eat’ had increased significantly. Ghrelin is a hormone associated with hunger – the more ghrelin in your system, the hungrier you’re likely to feel.

Like most fad diets, this suggests that post-diet:

Weight is regained rapidly as people compensate for the dietary restriction by eating more.

An interesting meta-analysis of 13 randomly controlled trials [ref 2] followed patients with overweight or obesity over 1-2 years. The patients followed either a low-fat diet, or a Keto diet. The study found that:

• Patients on Keto diets lost a small but significantly greater quantity of weight than patients on low-fat diets.
• The difference between diet types declined over time, as did the patients compliance with Keto.

The authors noted that by the end of the Keto diet, most patients were eating considerably more carbohydrate than the diet allowed.

This highlights a problem of many ‘fad’ diets – because they’re so restrictive, they’re very hard to stick to!

Does evidence highlight the danger of Keto?

According to researchers from the Harvard School of Public Health there’s a lack of quality research into Keto. Studies tend to be short (less than 12 weeks), have small numbers, and lack control groups.

By excluding so many foods, Keto is hard to sustain and therefore study long-term. Additionally, it can be hard to gain approval to study high-fat diets like Keto. Because such diets are linked to a variety of adverse health conditions:

• Ethics committees are unlikely to provide consent for research that may harm human subjects!

With these constraints in mind, two recent studies are noteworthy.

In the first, Swedish researchers investigated the effect of a Keto diet on cardiovascular risk factors [ref 3]. 24 healthy, young, normal-weight women were randomly assigned to either a four-week Keto diet followed by a control diet, or the reverse sequence. The diet ‘treatments’ were separated by a 15-week ‘washout’ period.

The macronutrient ratios in the diets were as follows:

• Keto – 4% carbohydrate, 77% fat, 19% protein.
• Control (the nationally recommended diet) – 44% carbohydrate, 33% fat, 19% protein.

In terms of results, the study found that:

The Keto diet significantly increased LDL-cholesterol in all participants.

The authors concluded that:

• Feeding healthy, young, normal-weight women a Keto-style diet induces a dangerous blood lipid (fat) profile.

The second study represented research presented by the American College of Cardiology [ref 4]. The study was ‘retrospective’. It analysed data from the UK Biobank, a large-scale biomedical database of genetic and health information from UK participants.

Based on a diet questionnaire, 305 participants were identified who had previously followed a ‘Keto-like’ diet. These people were matched by age and sex with 1220 individuals who had reportedly followed a standard diet.

After an average follow-up period of 11.8 years, the researchers observed that:

• Participants who had followed a Keto-like diet had significantly higher LDL-cholesterol levels.
• A Keto-like diet was associated with a two-fold heightened risk of cardiovascular events when compared to a standard diet.

The authors readily acknowledge limitations with the study, such as its reliance on self-reported diet measures. However, research is now making it reasonably clear that concerns regarding high fat diets should be taken seriously.

What is LDL cholesterol and why is it important?

Classified as a ‘sterol’, cholesterol is one of three types of lipids found in the body. The others being triglycerides (which make up the majority of the fat we consume) and phospholipids.

We often refer to lipids and fats interchangeably. Technically, they aren’t the same; lipids are a broad group of biomolecules whereas fats are a type of lipid.

With that technicality out of the way, let’s look at cholesterol…

Cholesterol is a waxy like substance found in every cell of the body. It plays a key role in important functions such as making cell membranes, hormones, and vitamin D.

Cholesterol comes from:

• The liver – which actually produces all the cholesterol the body needs, and
• The food we eat – predominantly animal foods such as meat, poultry and dairy products.

Cholesterol (and triglycerides) are transported through the bloodstream by particles consisting of lipids and proteins, called lipoproteins.

There are two major types of lipoproteins, namely:

• High-density lipoproteins (HDL) or,
• Low-density lipoproteins (LDL).

HDL is often referred to as ‘good cholesterol’. It transports excess cholesterol from around the body back to the liver for removal.

LDL is often referred to as ‘bad cholesterol’. It can build up and form ‘plaques’ within blood vessels which obstruct, and potentially block blood flow.

Consequently, high levels of LDL-cholesterol can increase the risk of heart attack and stroke.

Conversely, high levels of HDL-cholesterol can reduce this risk.

It’s notable that animal foods also tend to be high in ‘saturated fat’. A high intake of saturated fats causes the liver to produce more cholesterol than it normally would. This added production can cause people to move from a healthy, to unhealthy cholesterol level.

From a health perspective, doctors often look at a person’s total fat/lipid profile during health checks. High triglyceride levels combined with high levels of saturated fat and LDL-cholesterol is generally considered a ‘dangerous lipid profile’.

Such a profile is usually associated with a diet high in animal foods – lots of meat, poultry and dairy products. Exactly the type of diet advocated for by…Keto!

What’s the ultimate danger of Keto and other fad diets?

An increased risk of cardiovascular illness isn’t the only problem associated with Keto.

After switching to a low-carbohydrate intake, it normally takes 3-4 days for the body to fully deplete its stored glucose (glycogen) reserves. During this time people often start experiencing what’s become known as ‘the Keto flu’.

Common symptoms include headache, ‘foggy brain’, fatigue, irritability, nausea, difficulty sleeping and constipation.

By eliminating high-fibre plant foods; breads, cereals and starchy vegetables you’d expect constipation as an outcome. And by making the brain adapt to an alternate fuel (ketone bodies), cognitive symptoms such as ‘foggy brain’, fatigue and irritability also make perfect sense.

Additionally, health experts warn of ketoacidosis developing when a very low carbohydrate diet is followed for a prolonged period. A potentially fatal condition, ketoacidosis occurs when excessive ketone bodies produce a toxic level of acid in the blood.

Concentrated acid in the blood…sounds like something from my favourite movie Alien!

Fortunately, most people undergoing Keto are unlikely to ever develop ketoacidosis. The simple reason – people struggle to stick to Keto long enough for ketoacidosis to occur!

Herein lies the ultimate danger of fad diets like Keto – the radical changes they demand aren’t sustainable.

This fundamental flaw guarantees that lost weight is quickly regained once the diet finishes.

The mechanisms by which this works are discussed in this article from our Register of Weight Management Coaches.

In short, humans have developed a number of physiological responses that protect us from weight loss. You see, for the majority of human history, we lived in environments where food was scarce. Losing weight in such environments was dangerous and needed to be resisted!

As such, rapid weight loss, as achieved via restrictive fad diets such as Keto, is accompanied by:

• Significant increases in hormones that make us feel hungry, and
• Significant reductions in our metabolism (rate at which we burn energy).

These physiological responses:

• Act as a brake, limiting the amount of weight that can be lost.
• Remain active well after any diet finishes.
• Produce the ‘yo-yo effect’ when combined with a fad diet.

Here’s how it works:

1. Ani does Keto for 5 weeks and loses 8kg. While rapt with her weight loss, she’s relieved that the diet is over – ‘oh for some normal food’!
2. Following the diet, Ani returns to her normal eating habits and starts regaining weight.
3. Twelve weeks later Ani has regained all her lost weight + an extra 2 kilos. She’s devastated and blames herself – ‘it’s all my fault, I’ll diet again and stick to it this time’!
4. Ani does Keto again and loses another 5kg. Thinking that the diet has worked, Ani stops and returns to normal again.
5. With a lowered metabolic rate and increased hunger – Ani regains that 5kg + 3kg more within ten weeks.

And the cycle keeps repeating.

The diet is perceived to be effective, yet its flaws make weight regain inevitable. Blame is ascribed to the dieter with devastating effects which we describe in these articles.

This is the ultimate danger of fad diets like Keto.

A final word…

So, is Keto a fad diet?

In clinical settings it appears to be a legitimate diet for people with certain conditions.

As a weight-loss diet for the general population, it certainly appears faddish! It’s definitely not the long-term solution to our excess weight problem.

To solve a problem, you must understand the problem in the first place. This is where fad diets like Keto fall down…and are dangerous. They don’t address the many biological, psychological and environmental factors that contribute to our weight.

They imply that ‘failure’ is the individual dieters fault, rather than the diet.

By comparison, our Weight Management Coaching programme helps people develop a comprehensive understanding of all the factors that influence bodyweight. This understanding then shapes interventions that:

• Are tailorable to each and every individual.
• Support people to make sustainable behavioural changes that address the underlying drivers of excess bodyweight.

If you’re interested in finding out more about our Weight Management Coaching programme, feel free to enquire with your local campus.

References

1. Sumithran et al. (2013). Ketosis and appetite-mediating nutrients and hormones after weight loss. European Journal of Clinical Nutrition. https://doi.org/10.1038/ejcn.2013.90
2. Bueno et al. (2013). Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss. A meta-analysis of randomised controlled trials. British Journal of Nutrition. https://doi.org/10.1017/S0007114513000548
3. Burén et al. (2021). A ketogenic low-carbohydrate high-fat diet increases LDL cholesterol in healthy, young, normal-weight women. A randomised controlled feeding trial. Nutrients. https://doi.org/10.3390/nu13030814
4. Iatan et al. (2023). Low-carbohydrate, high-fat ‘keto-like’ diet associated with increased risk of CVD. ACC News. https://www.acc.org/Latest-in-Cardiology/Articles/2023/03/01/22/45/Sun-1215pm-kctogenic-acc-2023