The Low-Down on Low Carb Diets

low carbKetogenic, low carb, high fat, paleo, primal, Atkin’s – you’ve heard of them all, but what’s the deal with low carb diets and are they right for you?

Low carb diets exclude or minimise higher carbohydrate foods, such as grains (wheat, corn, oats and rice), starchy veggies, legumes and most fruits. Proponents of low carb diets say they can be used to accelerate weight-loss, manage insulin resistance, increase energy levels, reduce hunger and lower cholesterol. While this sounds great in theory, there are some key factors that need to be considered when attempting a low carb diet:

Fibre and Stool Regularity

Depending on what types of carbohydrates are restricted, a low carb diet is often a low fibre diet.  Fibre is only found in plant foods and so many of the high fibre foods are restricted in low carb diets. Whilst many low carbers still eat a wide variety of green veggies (as these are lower in carbs), restricting healthy fibres found in legumes, starchy veg and wholegrains can reduce overall fibre intake, giving rise to issues like constipation and bloating. In clinic, we often see new patients who have put themselves on a fad low carb diet and suffer bowel issues as a consequence.

Overall Nutrient Profile

Embarking on a low carb diet can alter the nutrient profile of your diet, restricting certain nutrients and increasing intake of others. Whilst a low carb diet can contain a wide array of vitamins, minerals and phyto-chemicals, some people interpret low carb as an excuse to load up on foods such as butter, bacon, eggs and steak, whilst consuming inadequate amounts of brightly coloured fruit and veg. As you can imagine, this drastically increases one’s intake of saturated fat and cholesterol, whilst limiting nutrient diversity. As always, a healthy diet should include a wide variety of foods from a wide range of food groups, with a particular emphasis on whole, fresh, beautiful plant foods!

Thyroid Function

Many people embark on a low carb diet as they’ve heard it can assist weight-loss.  It is important however to consider the effect a low carb diet can have on thyroid function. As adults, we need approximately 150 g of carbohydrates per day as a minimum to effectively convert thyroid hormone into its active form. As our thyroid is responsible for setting our metabolic rate, a long-term low carb diet may reduce circulating levels of active thyroid hormone, reducing the metabolic rate and eventually hampering weight-loss goals. We treat thyroid cases on a daily basis in clinic and sadly we are too often seeing poor thyroid function due to restricted diets that don’t provide either enough carbohydrate or enough of particular nutrients (think iodine, selenium, zinc etc) to ensure proper thyroid function.

Microbiome Diversity

As we’ve talked about HERE and HERE, a wide variety of plant foods is needed to optimise the health of your microbiome by increasing the diversity of bacteria colonising your gut. And when I say a ‘wide variety’, we’re talking up to 40 different plant foods a week! That’s a significant number in itself, but becomes almost insurmountable when you exclude certain foods from your diet, such as grains, legumes and/or starchy veg. Different types of fibre and phyto-chemicals found in plant foods selectively feed different species of bacteria in the gut, and therefore consuming a wide variety of starchy and non-starchy plants is necessary to optimise microbial diversity and support digestive function.

Satiety, Brain Fog and Energy Levels

While there’s no doubting some people feel great on a low carb diet (especially in the first few weeks or months), many of our patients report fatigue, low energy levels, brain fog or persistent hunger, despite eating regular meals. Carbohydrates contribute to satiety, and many people (particularly women, athletes and children) tend to feel better with more stable energy levels on a more balanced macronutrient profile. Whilst the brain makes up only around 2% of your body weight, it can use up to 20% of your blood glucose levels, which is why adequate carbohydrate consumption is so important for memory, concentration and learning.

Age and Stage Appropriateness

As I touched on above, very low carbohydrate diets are not right for everyone, in particular, children, high intensity athletes and those with certain medical conditions. This is why we recommend all of our patients speak to their naturopath first, before embarking on a low carb diet.


Lastly, we talk to many of our patients about balancing the acid load in their diet by paying attention to the Potential Renal Acid Load of the foods they eat. While this topic could be an article in and of itself, in essence, an alkalising diet is highly anti-inflammatory and can reduce the risk of osteoporosis long-term. Fruits and veggies have an alkalising effect on the body (largely due to their potassium content), whilst acid-forming foods include animal proteins, grains, nuts and seeds. For this reason, as many low carb diets are rich in animal proteins, they can have an ‘acid-forming’ effect on the body, increasing the risk of calcium metabolism issues such as kidney stone formation and osteoporosis.

Our Approach

As a general rule, we recommend a balanced dietary approach, rich in complex carbohydrates, lean proteins and healthy fats. We encourage our patients to consume an abundance of fresh fruit and veggies, whilst also including legumes, raw nuts and seeds, animal proteins and wholegrains in their diet. For some patients, we do recommend a low grain diet, as opposed to a strictly low carb diet. If you’d like to know more about the type of diet we recommend for you (or for particular health conditions like diabetes, cardiovascular disease and arthritis) we recommend you get in touch with our friendly admin team on 9285 0998 to book an appointment 🙂

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