Confused about which carbohydrates you should be eating? Welcome to the club. “It’s the biggest lack-of-consensus issue in diet today,” says Dr Dariush Mozaffarian, associate professor of epidemiology at Harvard School of Public Health. “We don’t have a standard method for assessing their quality.”
Ever since the likes of Dr Atkins’ New Diet Revolution hit the headlines over ten years ago, carbohydrates have been maligned as the food-group baddies – they make you fat, they’ll send your blood sugar through the roof, and they get you hooked on wanting more.
While the fad-diet brigade lusts after the short-term weight-loss statistics of low-carb, high-protein regimes like the Dukan – famously responsible for Kate Middleton’s super svelte physique – crowds of nutritionists and scientific researchers are rushing to defend the humble carbohydrate from its place in the diet stocks, arguing that they’re a vital part of realistic healthy eating plans.
“Carbohydrates are not the enemy, and should not be avoided at all costs,” says Laura Smith, nutritionist at Bespoke Nutrition in Dubai. “Our brains need the glucose from carbohydrates to function properly, so they are vital if you want a productive day and to feel healthy.”
But there’s no getting away from it – some carbs are better than others. You still need to stick to the good sources and steer clear of the bad ones, which are linked to obesity and a host of chronic conditions, including diabetes and heart disease. And for those fasting over the holy month, it could not be more important to choose the right types at iftar and at suhour. We ask the experts to make the case for carbs that should be released from diet prison, and those that should be locked up for life.
The good, the bad and the ugly
If you occasionally frequent the bakery aisle and have managed to resist the urge to join the carb-free lifestyles of the Middletons and Zellwegers of the world, the good news is you can give yourself a pat on the back. The fact that our bodies need carbs is the one point all the experts we spoke to agreed on. This gets further support from a recent study pointing to the higher risk of cardiovascular diseases in women who exclude this major source of nutrition from their diets.
Published in the British Medical Journal on June 26 of this year, the study sampled more than 43,000 Swedish women over 15 years and found that those who stuck to Atkins-style low-carb, high-protein diets had a 28 per cent higher risk of a cardiovascular event. Even slightly changing the dietary mix in favour of consuming more protein increased the risk to heart health. Just a 20-gram decrease in daily carbohydrate intake and a five-gram increase in protein intake led to a 5 per cent increase in the overall risk of cardiovascular disease.
This supports earlier findings of Greek researchers, who used data from the European Prospective Investigation into Cancer and Nutrition trial (EPIC) to follow the diets and health of more than 22,000 adults aged between 20 and 86 over ten years.
They found there was significantly lower mortality risk for adults with the highest carbohydrate intake, while diets richer in protein were associated with a higher risk of mortality. Subjects who combined the highest protein and lowest carbohydrate content in their diets had an even higher risk of mortality within the sample.
However, look hard enough and you can probably find a scientific study to back up any nutritional claim in some way or other. Instead, as a useful starting point, Dr Mozaffarian offers four main factors for determining the criminal record of a carb: how fast it makes your blood sugar rise (its glycaemic index or GI); its dietary fibre; its wholegrain content; and its structure. Here we explore these ideas and add another one, which will influence all of the above – your individual circumstances.
Most health experts agree that processed foods, sweetened beverages and refined grains such as white bread, pasta, flour and rice (which are stripped of their nutrients) are the worst offenders. Your digestive system breaks them down too easily, flooding the bloodstream with simple sugars (glucose), which prompts a surge of the hormone insulin to carry the glucose into the body’s cells, says Dr Michael Roizen, chairman of the Cleveland Clinic Wellness Institute.
Too much blood sugar and insulin for too long can be dangerous on several levels. It can mean more fat storage, less fat burning and malfunctioning proteins that eventually lead to organ damage, even cancer cell growth, Dr Roizen says. Your brain also gets addicted to the high glucose levels, leaving you craving more. A background check on the GI of the carbs you consume is the way forward. GI is the way to identify which carbs are quickly broken down to glucose (high GI) and those which are slowly broken down (low GI), explains Lovely Ranganath, senior nutritionist at Dubai World Trade Centre’s Event and Hospitality Services. Although research is ongoing, she says understanding the different rates at which carbs are digested may be a useful tool in the fight against obesity, heart disease and diabetes. “Instead of talking about no carbs or low carbs, the real answer may lie in slow carbs,” she says.
The jury is still out on the criminal status of wholegrains. “A well-balanced diet should include wholegrain choices as they provide important nutrients like chromium (in whole wheat), vitamins B1, B2, B6 (in oats, rye and wheat), and they can be an important source of fibre, which is important for healthy digestion and to reduce the risk of colon cancer,” says Dr Maria Ridao Alonso, medical director of the Specialist Preventative Medicine department at Dubai Herbal and Treatment Centre.
But Jonathan Bailor, a health and fitness researcher, advises you source carbohydrates from citrus fruits, berries and a host of non-starchy vegetables, such as spinach, and stay away from starches altogether – including wholegrains.
The best foods to eat, Bailor says, are those with greater water, fibre and protein content relative to their calories, so you get more bang for your buck.
“It’s not that wholegrains are evil; it’s just not as good for us as non-starchy fruits and vegetables,” says Bailor, who recently wrote The Smarter Science of Slim with based on the results of a decade of reviewing more than 1,000 diet studies.
Laura, an advocate of the Paleo (or caveman) Diet, has similar views. “The paleo lifestyle is a concept that promotes a shift back in time to the diet of our ancestors. The aim is to avoid grains, processed foods and sugars and starches. Eating a natural diet with fruit and vegetables, lean meats and fish, nuts and seeds and healthy fats has been proven, not only to aid weight loss, but also to improve blood-sugar levels, energy levels, sleeping patterns and blood lipids,” she says.
Laura believes that by consuming carbohydrates from non-starchy vegetables and fruits, you will not only balance out your blood-sugar levels, but your intake of vitamins, minerals and antioxidants will also increase, pointing to their probable role in the prevention of various diseases associated with oxidative stress, such as cardiovascular disease, neurodegenerative diseases and certain cancers.
Dietary fibre and structure
Dietary fibre is not considered a form of energy the same way conventional carbohydrates are, explains Lovely. “Human digestive enzymes cannot break the bonds that hold its sugar units together,” she says.
As a rule of thumb, Dr Mozaffarian recommends that you look at the ratio of total carbohydrates to dietary fibre in a serving, as that allows you to understand both the sugar and starch content. If the ratio is 10:1 or more, avoid it. If it’s less than 5:1, it’s very good.
Lovely adds that a form of fibre that has been receiving a lot of attention at the moment is resistant starch, which is starch that resists digestion. This type of fibre is only digested by friendly bugs in the colon and may improve gut health. “We may see more of resistant starch in the near future in the form of functional foods – foods that are specifically designed to offer a particular health benefit,” she says.
According to Laura, resistant starch – found in seeds, legumes, and unprocessed wholegrains – has similar beneficial properties to insoluble and soluble fibre. “It resists digestion in the small intestine and passes through the large intestine. It is during the passing through the large intestine that the resistant starches act like a fibre.” She says that maintaining an unprocessed natural diet with resistant starches has been shown to aid with weight loss, both by lowering calorie intake and keeping you feeling full for longer.
As far as the structure of a carbohydrate is concerned, Dr Mozaffarian says if it’s liquid, milled or pulverised, it’s not as good. So a popular breakfast cereal like Cheerios, that is made of 100 per cent wholegrain oats, get a thumbs up for wholegrain and fibre content, but the pulverised nature of the oats makes it inferior to intact wholegrain cereals, such as steel-cut oats.
While there are some general areas of consensus among the experts, they point out that there are no uniform rules when it comes to selecting carbs. Dr Alonso says, “My advice is not to look out for the one-size-fits-all advice, rather go for assessments. People, their lifestyle, their genetics and needs are different.”
Laura agrees: “Take an elite athlete for example; starchy foods are vital for them post-workout. Various studies have shown that a meal containing high-GI foods with roughly 1-1.5 grams of carbohydrates per kilogram of body weight can mean an athlete will reproduce maximum performance 24 hours after an intense workout. This is helped by small, regular consumption of low-GI foods throughout a recovery period.”
For children, she recommends a diet that includes 55 to 60 per cent of calories consumed from carbohydrates. “The key is to make sure they are obtained from good sources, and that added sugar in their diet is limited,”
Lovely says we need to consider to individual health issues too. “Some people have a hard time handling carbohydrates. For example if you have type 1 diabetes, your pancreas does not produce enough insulin to carry all the glucose produced from carbohydrates into your body cells.
If you have type 2 diabetes you can produce insulin, but your cells are resistant to it. As a result, the glucose continues to circulate in your blood until it is excreted through the kidneys.
“Other people can’t digest carbohydrates because their bodies lack the specific enzymes needed to break the bonds that hold a carbohydrate’s sugar units together. For example many are deficient in lactase, the enzyme that splits lactose (milk sugar) into glucose and galactose.”
So, after all this, what can we conclude? If the confusion surrounding carbs makes you want to reach for a bowl of mac and cheese, rest assured that everyone can agree on this: Eating lots of non-starchy vegetables does every body good.
What’s wrong with a low-carb diet?
According to Dr Maria Ridao Alonso, one reason for potential increased cardiovascular risk from low-carb dieting might be because in order to reduce carbs and increase protein, people often use protein from animal sources, which increases cholesterol levels. “They might provide quicker results in weight loss, but that comes at a high cost.”
In addition to increased risk of cardiovascular problems, kidney disease and the other health issues related to cutting carbs, the very nature of the diet is questionable. According to Lovely, “The key message that many low-carb diets convey is that carbohydrates promote insulin production, which result in weight gain. Therefore by reducing carbohydrate intake, you can lose weight. Unfortunately, this is just another nutrition myth.
“Many low-carb diets actually do not provide sufficient carbohydrates to your body for daily maintenance. Therefore your body will begin to burn stored carbohydrates (glycogen) for energy. When your body starts burning glycogen, water is released. The drastic drop of weight at the beginning of a low-carb diet is mostly the water that you lose as a result of burning glycogen.
“The truth is that low-carb diets are also often calorie-restricted. Therefore, it doesn’t matter if you eat a high-or low-carb diet, you will lose weight if you decrease your caloric intake to less than is needed to maintain your weight.”
Take this list shopping to help you weed out the bad carbs
- Brussels sprouts
- Low-fat Greek yoghurt
- Sweet potatoes
- Black beans
- Kidney beans
- Brown rice
- Wholegrain bread
- Wholegrain pasta
- Soft drinks
- Sports drinks
- Fruit drinks
- French fries
- White rice
- White bread
- Sugar-sweetened cereals
- Potato chips
- White crackers
- Brown sugar
- White potatoes
- 100 per cent fruit juice (limited quantities)