Ever tried giving up bread and pasta to shift the pounds? Well, the Ketogenic or Keto diet takes low-carb eating one step further…
Invented by doctors at the Mayo Clinic in the US, it’s been practised since the 1920s and is essentially a very low-carb, high-fat diet that puts your body in a metabolic state called ketosis.
This is a process that means your body uses fat for energy instead of glucose. There’s no counting calories here – it’s simply about changing the source of fuel your body uses to stay energised.
How does the Keto diet work?
When your body has limited access to glucose it starts to use fat for fuel instead.
The theory is that by eating very few carbs and removing certain foods from your diet, such as sugary treats and grains, and cutting down on potatoes, some fruits, and legumes, you encourage your body to go into the state of ketosis.
Dr Kristie Sullivan, author of A Journey Worth Taking: Cooking Keto with Kristie and new book Keto Living Day-by-Day (out in March) says: ‘There are different levels of low-carb, but a Ketogenic diet is by definition one in which 70% or more of calories are derived from fat, 25% from protein, and five per cent or fewer from carbohydrate.
‘The idea is to starve the body of glucose so that your body burns fat instead.’
Can you lose weight on the Keto diet?
It does seem to be effective at shifting the pounds. A 2003 US study on healthy but obese women showed that a very low-carbohydrate diet is more effective than a low-fat diet for short-term weight loss, although later studies have challenged this thinking.
When it comes to how quickly you will lose weight, everybody is different and, as with many diets, if you have a lot of excess pounds to shed, you may notice faster weight loss in the beginning, which may then slow down.
What can I eat on the Keto diet?
You can eat lots of fat, including butter, mayo, and oils. Healthy fats such as olive oil, and nuts and seeds are also on the ‘yes’ list. You can also eat non-starchy veg, such as leafy greens. In addition, you’re allowed meat, poultry, fish and some full-fat dairy.
Water, coffee and tea are OK with modest amounts of milk, and you can even have the occasional glass of red wine.
A typical day could include bacon and eggs for breakfast, baked salmon with spinach for lunch, and a steak with salad for dinner.
What can’t I eat on the Keto diet?
Carbs are all but banned, so that’s goodbye to bread, potatoes and pasta, while fruit, beer, rice, processed foods high in sugar, and anything made with flour or grains are also a no.
Isn’t it like the Atkins diet then?
Both diets are low-carb, but the Atkins diet differs in subtle ways, mainly that it is high in protein, whereas the Keto diet is not.
What are the benefits of the Keto diet?
Dr Kristie Sullivan is a firm believer in the diet and says, ‘When I began a very low carb or Ketogenic diet in 2013, I weighed over 263 pounds. I was on three different pain medications and had limited mobility because of issues with my back.
‘After losing 120 pounds, I simply feel good, even as I age. I have more energy, I ride bikes and I run.’
Besides weight loss, some proponents say they feel less hungry and fuller on the diet.
What are the negatives?
While some people claim to feel great on the diet, others don’t, and side effects can include headache, fatigue and constipation.
Registered Nutritionist Charlotte Stirling-Reed warns: ‘As a Registered Nutritionist, I’m not a fan of any diet. However, I have concerns with this one in particular, as carbohydrates make up a wide range of everyday foods.
‘A diet without them is therefore heavily restrictive and, for many, cutting out these foods is very hard.’
Additionally, a 2010 study published in the Journal of the International Society of Sports Nutrition revealed that a low-carb diet may not provide enough of some B vitamins, vitamin E or calcium.
The diet is also low in fibre (hence the constipation) so you need to watch your digestive system is working properly, and may even need to take supplements – but consult your GP before doing so.
Does the diet include exercise?
According to theketogenicdiet.org, ‘When you are in a state of ketosis and all of your fuel is coming from fat, you don’t need to exercise to burn it off and lose weight.’
However, there are many important health benefits to regular exercise. Just listen to your body and don’t overdo it, particularly if you are on a restrictive diet.
Is the Keto diet safe and sustainable?
Experts differ on the subject. Registered Dietician Alison Cark says: ‘This isn’t a diet I would recommend as, firstly, it isn’t sustainable in the long run and, secondly, you cut out a whole food group: carbohydrates and whole grains that are required for optimal health and wellbeing.
‘There are also a lot of side effects commonly associated with this type of diet, which may last for several weeks.
‘Additionally, there is a lack of long-term research into the safety and effectiveness of Ketogenic diets.
‘From professional experience, people who embark on this type of diet do lose weight but end up putting it – and possibly more – back on, as they’ve not made lifelong, sustainable changes to their diet and lifestyle.’
On the flip side, Dr Kiristie Sullivan argues: ‘A good, “clean” Ketogenic diet – which means eating real, whole foods and healthy fats (excluding seed and industrial oils), while avoiding processed products – is safe.
‘Although the diet has become popular for weight loss, it really is a tool to manage overall health and is meant to be followed long-term.
‘Short-term, as with any “diet”, if you begin eating as you did before, then you invite the same issues you faced before starting it.’
Who should avoid the Keto diet?
People with heart disease are often advised not to try this diet. ‘Plus, it’s not suitable for people with type 1 (or late stage type 2) diabetes, unless under medical supervision, as there could be a risk of ketoacidosis, where ketone levels become dangerously high,’ warns Alison Clark.
‘Anybody considering this diet should speak to their doctor first, particularly if they are pregnant, breastfeeding, underweight or have a medical condition, as they may need close supervision.
‘There are some medical conditions that do use the Ketogenic diet, but this should be done under medical supervision only.’
