A low-carb diet: Why it works
By Dr Michael Mosley
In recent years, I have noticed that everyone seems to be obsessed by the low-carb Keto Diet. For those not familiar, this diet, favoured by celebrities such as Kim Kardashian and Megan Fox, is a high-fat, very low-carb regime.
The idea is that eating minimal amounts of carbs will force your body to burn fat instead by turning fatty acids in your blood into ketone bodies.
The body (and brain) then uses these as fuel instead of glucose from carbohydrates.
So, what is Keto?
Keto is a jazzed-up version of the age-old low-carb, high-fat approach, which was first written about by undertaker William Banting more than 150 years ago.
Banting, who was 5ft 5in and 14st, wrote a booklet entitled Letter On Corpulence, which detailed his attempts to tackle his obesity by eating a low-carb diet (though he didn’t call it that). He gave up sugar, potatoes, beer and bread and instead stuck largely to meat, greens, fruits and dry wine. He lost 3st in a year, and his book became a bestseller.
And so the low-carb diet was born, popping up in a host of variations throughout history (the Atkins Diet, for example). They are not greeted with much enthusiasm by doctors or dieticians as you have to eat a lot of fat. Clinical trials, however, consistently show that low-carb diets are effective for weight loss, over and above low-fat diets that once proved popular for those slimming down and watching their weight.
Are all carbs bad?
Not all carbs are created equal; just as there are good fats and bad fats, there are good carbs and bad carbs. The trick is not to cut carbs completely, but rather to be choosy about the ones you regularly eat. If you want to try going lower-carb then white bread, white pasta, potatoes and sugars, including maple syrup and agave nectar, are best eaten sparingly, if at all. They are easily digestible carbohydrates, meaning they are rapidly absorbed by the body, creating a big spike in your blood-sugar levels.
Instead, eat carbohydrates that contain lots of fibre. Fibre reduces the blood sugar spike, provides protection against bowel cancer and feeds the ‘good’ bacteria that live in your guts. Examples include vegetables, legumes – chickpeas and lentils – and wholegrains such as barley, oats, buckwheat, and wholegrain and rye.
Dr David Unwin, a GP in Southport, (who tweets as @lowcarbGP) has developed and tested a sensible approach to a low-carb diet.
David, winner of the NHS Innovator of the Year award, recommends his overweight patients try to cut out sugar and cut down on white (easily digestible) carbs such as bread, pasta and rice. He recommends eating plenty of blueberries, strawberries and raspberries, which are relatively low in fruit sugar, and green vegetables, protein, butter, full-fat yogurt and olive oil to retain fullness.
In a recently published study, patients following his advice lost almost 1½st on average, and 6in around the waist. There were big improvements in blood pressure and cholesterol levels too, and many of those with type 2 diabetes were able to come off medication. His GP practice is now saving more than £38,000 a year on its diabetes drug budget alone. Not bad for a ‘fad’ diet…
Carbs: how low should you go?
Medical evidence suggests that over the long-term, following a Keto Diet may not be achievable as it is a little more restrictive. However, it can be a useful tool for a kickstart to your weight loss before moving on to a more long-term, sustainable approach. If you are thinking about a Keto Diet, opt for fresh, healthy food, rather than processed options with a “keto” label and a high price tag!
The traditional Mediterranean-style diet, based on unprocessed carbs, healthy fats, fresh vegetables and fruit, has been granting long life and good health for many centuries, and – studies show – is still doing so today.
The Mediterranean-style diet is built around unprocessed, whole foods. Legumes, brown rice, barley, oats, buckwheat and rye break down slowly in the body, releasing energy steadily through the day.
Low-carb, not low-fat: five practical steps
- Avoid processed carbohydrates and always check the label for added sugar. This includes fructose, glucose, maltose and other ingredients ending in “–ose”. Also, avoid syrups and juices, either as ingredients or as beverages.
- Instead, go low and go slow: a relatively low-carb diet will give you a slow release of glucose. Choose legumes, brown rice, oats, rye, barley and other wholegrains too.
- Cook, cool and reheat carbs like pasta, potatoes and rice. Dr Denise Robertson, of the University of Surrey, found that cooling and reheating pasta changes the structure of starch in the pasta, making it more resistant to digestive enzymes and leaving you with smaller, more manageable, blood sugar spikes.
- To succeed on a low-carb diet, increase your intake of healthy fats. Focus, in particular, on foods rich in olive oil and omega-3 oils. Olive oil is a very powerful ingredient; responsible for the bitter taste in olive oil, oleuropein has been shown to have cholesterol-lowering and anticancer effects. Further evidence also suggests that oleuropein may be able to help protect against Parkinson’s disease and Alzheimer’s.
- Increase your fibre intake: a Mediterranean-style low carbohydrate regime is naturally high in fibre. This helps you to feel fuller for longer.