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Popular diets, what's wrong with them

This post is a follow on from my previous post about why sticking to one diet is ruining your health. You can check that article out here

Diet books are a multi-million pound industry. We are constantly being navigated towards the latest trends and the newest diet touted to be the next BIG thing. The most popular diets seem to be paleo, ketogenic, vegan, raw vegan. Now, many devoted people will tell me "It's not a diet, it's a way of life!" But that's entirely the problem. We shouldn't be truly devoted to one diet because our dietary requirements and needs are constantly changing based on our age, activity level, hormones, digestive ability, gut health, disease status and overall wellbeing.

The “perfect” diet that once healed your digestion and cleared up your complexion is now making you feel tired, lethargic and bloated. You must be objective when it comes to your own health. Nobody knows your health status better than yourself. Not a diet book, not your doctor, not your personal trainer. Learn to understand and listen to the signals you are getting from your body.

Here is a list of most common deficiencies, from popular diets, and their potential effects on your body:


Diet restrictions:

It depends on the type of vegetarian you are, but commonly, no meat, poultry, dairy, or foods containing animal products.


Vitamin B12 (1), found in animal products and shellfish. EPA & DHA (2), found in fatty fish. Vitamin D3 (3)

Potential effects:

B12: Reduced immune function, autoimmune disease, Brain fog and memory problems.

DHA: Risk of depression, Alzheimer's, fatigue, brittle nails, mood swings

Vitamin D3: muscle weakness, bone pain, often sick/poorly, increased risk of bone fractures


Diet restrictions:

Vegans, in addition to being vegetarian, do not use animal derived products and by-products such as eggs, dairy products, honey, leather, fur etc.


several studies have shown common deficiencies in B12, calcium, iodine, iron and the omega-3 fatty acids (4,5,6,7).

Potential effects: Calcium: Development of Osteoporosis, muscle cramps, fatigue, course hair

Iodine: Reduced thyroid function, potential development of hypothyroidism

Iron: Exhaustion, pale skin, restless leg syndrome, anxiety, shortness of breath, hypothyroidism

Omega-3 fatty acids: Dry skin, soft brittle nails, attention span issues, difficult sleeping, inflammation

Ketogenic Diet:

Diet restrictions:

The exclusion of high-carbohydrate food sources such as starchy vegetables, rice, bread, pasta, grains, sugar etc, with a very high fat intake and low/moderate protein intake.


This diet is known to cause mineral deficiencies in sodium, potassium and magnesium. These are important for brain function, heart, muscle and bone health, energy production and blood pressure regulation (8, 9, 10, 11, 12)

Potential effects:

Sodium: Sleep disturbances, dehydration, muscle twitching, low blood pressure

Potassium: Fatigue, lightheadness, headaches, diarrhoea, frequent urination, dehydration,

Magnesium: Reduced sleep quality, loss of appetite, weakness, osteoporosis, muscle cramps


Diet restrictions:

No legumes, grains, reduced sugar, no dairy. Focuses on free-range meats, seafood, vegetables, nuts and starches.


Due to its low-carbohydrate method, some people report experiencing fatigue, weight gain (due to reduced thyroid function), loss of monthly period. These could be attributed to a significant decrease in iodine, sodium, calcium and thiamin (13, 14, 15)

Potential effects:

Iodine: Unusual weight gain, reduced thyroid, menstrual problems, depression

Sodium: Sleep issues, dehydration, low blood pressure

Calcium: Osteoporosis, muscle cramps, hair and nail health

Thiamin: Reduced energy, digestive issues, reduced metabolism

Highlighting the pitfalls of modern day diets allow us to understand the complexity of the human body and shows us that there is no such thing as the best diet. However, one commonality they share is that they attempt to increase the intake of vegetables and limit the intake of processed foods. That is always the foundation of a good diet.

On the other hand, many people will argue that these deficiencies can be addressed with supplementation. That is correct, however, the point is to bring awareness to the limitations of each diet so that you can continue to optimise your health in the long-term, even if that means changing your diet completely.

When you remove the rules you open up the possibilities. What rules have you removed recently?

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