Carbohydrates are a complicated business when it comes to eating healthy and losing weight.  It's not easy when the advice seems to contradict itself, with some diets telling people to cut out carbs completely and others touting the benefits of a carb-laden eating plan.  However, recent research conducted at the Boston Children's Hospital seems to have finally laid the carb question to rest, as findings suggest that processed carbohydrates are not only bad in themselves but that they can trigger cravings for further calorie-laden, sugary goods.  

So it's not as simple as just eating better.  We all know that eating too much junk is bad for us but up until now, there has been a wide-spread belief that all calories are equal and that to lose weight, all one needs to do is to eat less, move more.  Whilst that in itself is not a bad premise, Dr. David Ludwig and his team at the New Balance Foundation Obesity Prevention Center at the Boston Children's Hospital argue that all calories are not, in fact, equal because they can affect the brain and the metabolism in different ways (Anahad O'Conner, 27th June 2012).  In fact, their research shows that some calories can actually encourage you to eat more unnecessarily, making them much more dangerous than their alternatives.  

Carb Cravings and Food Addiction

In order to prove their theory, Ludwig et al. took a sample of twelve obese men and gave them two milkshakes: one stuffed with 'bad carbs', and one with 'good carbs'.  Both drinks were identical in terms of calorie density, levels of carbohydrates, protein, and fats, and were tested for equality in flavor (the men claimed to have no preference for either milkshake).  However, one milkshake was made with a high glycemic corn syrup (the bad carb), whilst the other was made with a low glycemic carbohydrate and artificial sweeteners (the better alternative).  As expected, the high glycemic shake initially caused a massive blood sugar spike, whereas the low glycemic drink released energy slowly and consistently.  However, the research team continued to test their subjects after drinking the shake and it is what happened hours after that is the most interesting (Anahad O'Conner, 27th June 2013).  

Around four hours after drinking the high glycemic milkshake, the men reported feeling more hungry than they did with the alternative drink and their blood sugars plummeted to a dangerous hypoglycemic range.  What's more, brain scans demonstrated high levels of activity in the nucleus accumbens, the part of the brain associated with reward, pleasure, and cravings.  Interestingly, the nucleus accumbens is known to be involved in addictive behaviour and is linked to substance abuse and dependence, suggesting that food addiction is not simply a case of being greedy or having a proverbial sweet tooth but may be the result of something more sinister (Richard Gray, 26th June 2013).  

Thus, it is this brain activity that can encourage overeating - and in particular, cravings for more refined carbs and processed foods.  When blood sugar drops as it does after the initial spike caused by high glycemic foods, the body naturally seeks out foods that can restore it to its original levels, leading to a nasty and unhealthy cycle of fatty, sugary, carb-laden foods.  "It makes sense," Dr. Ludwig explains, "that the brain would direct us to foods that would rescue blood sugar, that's a normal protective mechanism" (cited by Anahad O'Conner, 27th June 2013).  

Trustworthy Results?

Previous studies have produced similar results to this one but have been considered less significant because of their method.  The great thing about Ludwig's research is just how similar the milkshakes were - even down to taste.  Previous studies though, have examined the reaction to the carbohydrates in cheesecake with the reaction to broccoli for example - a perhaps unfair comparison.  With the milkshakes, the outcome of the test cannot be down to a simple preference or a previously learned behavioural reaction to 'treats' such as cheesecake, and thus the results are more significant.  

However, the test sample was very small, involving just twelve men - a sample that many would claim is too small to prove a hypothesis.  In order for the results to be truly significant, they would need to be replicated on a much larger and more general scale; which may or may not produce different results (Tia Ghose, 26th June 2013).  Even so, Ludwig remains sure of his discovery as the reaction in all twelve men was the same and that the difference between the two test conditions (the differing milkshakes) was substantial.  He argues that "based on the strength and consistency of the response, the likelihood that this was due to chance was less than one in one thousand" (cited by Anahad O'Conner, 27th June 2013).  

So Are All Carbs Bad?

Carbs have been getting a bad name for themselves and now it seems that they are even worse.  It is known that over-consumption of refined carbs can lead to obesity, diabetes, heart disease, cancer, and now food addiction too but does that mean that we should cut out carbs completely?  Not at all.  In fact, many carbohydrates are extremely good for us and a balanced diet filled with unprocessed carbs, wholefoods, and fruits and vegetables is the best option.  By cutting out the bad stuff (the white bread, bagels, white rice, soda, sugary snacks, and so on), and replacing them with whole grains and green veg, you will become healthier, fitter, and have more energy (goodcarbs.org, 2013).  So in answer to the dreaded carb question: don't cut them out completely but by avoiding processed carbs, you'll not only lose weight but you'll make it easier on yourself by reducing your urges too!  

References

Anahad O'Connor, June 27th 2013, How Carbs Can Trigger Food Cravings [online], available at: <well.blogs.nytimes.com/2013/06/27/how-carbs-can-trigger-food-cravings> [accessed 18th August 2013]

GoodCarbs.org, 2013, The Carb Question [online], available at <www.goodcarbs.org> [accessed 18th August 2013]

Richard Gray, June 26th 2013, Chips and White Bread Trigger Cravings in the Brain [online], available at <www.telegraph.co.uk/foodanddrink/foodanddrinknews/10144347/chips-and-white-bread-trigger-cravings-in-the-brain.html> [accessed 18th August 2013]

Tia Ghose, June 26th 2013, Why Carbs May Cause Food Cravings [online], available at: <www.livescience.com/37768-refined-carbs-create-food-cravings.html> [accessed 18th August 2013]