The Ketogenic diet has taken the nation by storm with many Hollywood A-listers following this ‘fashionable’ way of life. But, how does this extreme nutrition plan work – does it really have ‘magical’ powers? And what are the implications on our health?
The theory behind Keto
The Keto Diet is an extremely low carbohydrate, high fat and moderate protein diet. It focuses on healthy fats such as avocados, nuts and oils and limits carbohydrates to around 50g a day. To put this in to perspective, that is roughly one cup of oats or a medium sweet potato – not much! After 3 or 4 days of such a chronically low dose of carbohydrates, you go in to ketosis. This means that you basically force your body to burn fat instead of glucose.
It is important to understand, however, that burning fat does not equals losing fat – you are just using it as an alternative energy source to carbohydrates.
The truth is that your body will lose fat whenever it is in a calorie deficit which is exactly what the Ketogenic Diet does. The severe lack of carbohydrates reduces your calorie intake which results in fat loss. It is as simple as that. There is no magic behind it.
The Ketogenic diet is a very low carbohydrate, high fat diet that has become very popular in recent years.
Does keto really work for weight loss?
The answer is yes. In fact, the DAA says those who follow a keto diet will ‘undoubtedly result in short-term weight loss’. But, as I pointed out, this is due to ‘a reduction in total energy (kilojoule) intake, the depletion of liver and muscle glycogen stores and associated water, and a reduced appetite’, not any superior fat burning effect. As per the law of thermodynamics, it comes down to calories in v calories out. It is, however, a short term solution to a long term issue. The success lays in being able sustain the weight loss over time.
Keto vs Other Diets
Whilst it seems clear that anyone adhering to a keto diet will lose weight, numerous studies have demonstrated that low-carbohydrate diets have no benefit over any other calorie restricted method. A very recent year long Randomised Control Trial called the DIETFITS study concluded that that low-carb and low-fat diets led to the same results when calories were matched.
The key is to find the best approach that suits you and if this means cutting carbs instead of fat, then give it a try! If, however, you love your carbs then keto may not be for you.
The Ketogenic Diet has no superior benefits to any other short term weight loss programme so find the method that best suits your lifestyle.
Does keto have health benefits?
There has been some evidence to suggest that following a ketogenic diet can improve our risk of cardiovascular and other serious diseases and benefits those with Type 2 diabetes (Westman et al. 2008).
However, a study by Dasinger et al (2005), which studied a number of calorie restricted diets, concluded that it was the reduction in weight loss that was the determining factor that improved health markers, NOT the composition of the diet:
“Cardiac risk factor reductions were associated with weight loss regardless of diet type [or therefore composition], underscoring the concept that adherence level rather than diet type was a key determinant of clinical benefits”
A further study by Truby et al (2006) looked at 4 commercial diets and showed that weight loss over time significantly reduced blood pressure, but it was the reduction in weight that had the greatest impact, not the diet itself.
Losing weight can dramatically improve health regardless of how it is achieved.
With that said, there is some promising research (Lambrechts et al. 2016, Zamani et al. 2016) to suggest that a keto diet can have extremely positive impacts on those who take medication for epilepsy, particularly children. It has been shown to significantly reduce the risk of seizures, more so than conventional treatment. Epileptic seizures can seriously reduce quality of life, so a keto approach could offer some major benefits that outweigh the disadvantages.
It is important to note, however, that different people will require different levels of carbohydrates to get in to nutritional ketosis; very often people believe they are in ketosis when really they are just consuming a very low carbohydrate diet.
A keto diet could greatly benefit children who are being medicated for epilepsy.
Factors To Consider
So, it is the adherence to a calorie deficit that appears to be the factor determining the success of losing weight with the Keto Diet, and indeed any other diet. Furthermore, research is emerging to suggest that sustaining the Keto Diet is very difficult. It does not easily fit in with family meal times and can make social events almost impossible. It’s restrictive nature does not promote optimal health which is defined by the World Health Organisation as:
“…a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.”
People, therefore, often eventually revert back to their previous eating habits. This highlights the notion that the best ‘diet’ is one that fits in with your lifestyle so that you can maintain a healthy weight longer term.
How safe is the keto diet?
When following the ketogenic way of life, it is extremely difficult to include enough nutritious fruits, vegetables, whole grains and dairy in your diet. A study by Katz and Meller (2014) advocates a diet rich in whole grains for optimal health which the Keto Diet cannot provide.
A standard ketogenic diet is made up of 30 per cent protein, 60 per cent fats and 10 per cent carbohydrates. Fundamentally, a diet that is 60 per cent fat will not provide you with all the essential vitamins and minerals necessary to human health not to mention the lack of fibre!
It can also have the following side effects:
- Disturbed sleep
- Low energy levels
- Increased hunger, although some people experience the opposite
- Digestive issues
- Reduced exercise performance
- Bad breath
Following a ketogenic diet can lead to nutritional deficiencies and impact on family and social events.
Is the Keto Diet efficacious? Yes, it is. Does it have superior benefits over any other calorie-controlled diet? No, it appears not, unless you suffer with epilepsy. The most effective ‘diet’ is one that you can stick to in the long term. When choosing your approach, make sure you weigh up the pros and the cons within the context of your lifestyle. As Steve Novella nicely puts it ‘long term weight control requires sustainable strategies not quick fixes and not magical diets’.
If you would like to learn more or discuss any of the points further, please get in touch with Rebecca Flannery, Evidence-based Nutritionist.