A show was broadcast by the BBC a few weeks ago called "The truth about carbs", and it made me all kinds of angry. Lots of you asked me to provide some clarification about the information provided in the show, so here goes!
While I watched, I kept notes (around 4 pages) and decided there were 4 key issues with the programme:
The experts used.
The language used.
Lack of evidence-based science.
Misrepresentation of facts.
There was only one nutrition professional on the show. The presenter was a GP, who mentioned that he had a degree in public health. Having done a public health degree myself, I can assure you nutrition education on these courses is very limited. What's more, nutrition education on medical degree courses is limited too. In fact, it is so poor in general that the Association for Nutrition (my governing body) have teamed up with the General Medical Council to improve things. The other professionals featured included two other GPs, a biologist and a dietitian. The biologist may have some background in nutrition, but this was not made clear. Of course the dietitian should have an in-depth background in nutrition, however I did not agree with everything she said. (Although, her segments could have been edited in a way that misrepresented her info.)
The show put carbs in a negative light from the outset with their language.
Even the title- "the truth about carbs"- indicates that there is something we do not know about carbs, or what we know is not the truth.
"How can we make carbs work for us?"- implies that carbs don't serve us, but they do.
They also created a good/bad rhetoric on carbs. This dichotomisation is not helpful at all.
"the wrong kind of carbs"
All these terms indicate that there is a right/wrong source of carbohydrate, that carbs are good or bad and that some are bad quality. None of these things are true. All carbs, and indeed all foods, serve us in some way. All sources of carbs provide us with energy, for example.
They also spoke about different type of carbohydrates, referring to sugar as white carbs, starch as beige carbs and fruit and veg as green carbs. They indicated that green carbs won't make you fat, but white and beige carbs do. This is of course false- weight gain is, in it's simplest terms, caused by consuming more energy than you expend. The content or source of the energy has no bearing on weight gain (of course it would be difficult to consume an excessive amount of most veggies, and it would definitely result in a sore jaw!).
Much of the language used sensationalised the topic.
"The carbs are all around us, we sit at our desks and get fatter and fatter, and that's why carbs have been demonised"- Carbs are all around us because they are a vital source of energy in the diet, they are easily accessible, cheap, nutrient dense, easy to cook and generally very tasty. Laying all the blame for our population's health issues is hugely misguided.
"Not that terrible milk chocolate"- Seriously? Milk chocolate is the most popular chocolate, and saying it is terrible is an opinion not a fact. If you love milk chocolate, don't stop eating it because a biased TV show told you to- food selection can be based on pleasure, as well as health. Enjoy your food.
"Beige and white carbs are everywhere, they can be hard to avoid"- You do not have to avoid any foods. Beige and white carbs are as important as green carbs! Fruit and veg is great and should feature heavily in our diets, but other carbs have a place too. Beige and white carbs are the best source of energy. White carbs provide quick release energy, which is useful in lots of situations. And again- they are cheap, readily available, tasty....All valid reasons for choosing food.
Look at all these quotes. What do any of these things actually say? Does any statement add to our knowledge?
All they have done is create unnecessary food fear around carbohydrates.
Lack of evidence-based science:
The show features some "experiments".
The first is the "cracker test", where participants were asked to chew a plain cracker and put their hand up when the test changed and became sweeter. This was timed. Now the theory behind this is that when you eat a starchy food, the enzyme amylase in your mouth starts to break down the starch into glucose (sugar). People who notice a flavour change quicker are said to have greater levels of amylase in their mouth and therefore can tolerate a greater level of carbohydrates (because they have a less severe blood glucose spike). This sounds reasonable, however this is not a scientific method. I have been unable to find any scientific literature that has tested the validity of this test or in fact the theory behind it. (It was featured in a book in the 1990s.)
Based on this "test" told us "some of you can eat as many as you like, but some of us have to watch it"..... Telling people to cut down (or cut-out) whole food groups based on an unproven test seems unethical to me. But hey, it was on TV, right?
The other experiment I take issue with is the exercise test the presenter took part in. He was asked (by a sports science researcher) to cycle for 30 minutes on a stationary bike on two occasions. On both occasions he swirled a liquid in his mouth for 10 seconds and spat it out, and repeated this every 5 minutes. One liquid was water and the other was a carbohydrate solution (think Lucozade Sport). Apparently he didn't know which was which. The results from both cycles indicated that when the carbohydrate solution was used his exercise output increased and we were told he cycled further and expended more calories, compared to when the water was used.
The theory behind it is that when receptors in your mouth detect glucose, they tell the brain that energy is on its way and the brain tells the rest of the body to increase it's work rate, as fuel will be coming. Again, sounds very plausible.
But I have some issues with the test we saw:
He surely knew which drink was which- the carbohydrate drink will have tasted sweet. If participants know which they are consuming it can affect the results.
They did not tell us what happens if you ACTUALLY DRINK THE LIQUID. Surely, exercise output would improve further if the energy promised actually came? We were never told whether drinking a carbohydrate drink provided further improvements that swirling it in your mouth. Ideally, they would have done a cycle swirling water, one swirling carb solution, one swallowing water, one swallowing carb solution and one doing nothing. Then we would be able to truly compare the results.
Is this something that is useful for the population? Surely, nobody who watched the show will be taking a spit bucket to the gym with them (you may lose your membership!!) and spitting away £££ worth of sports drinks. And if it is not a useful tool for the general population, why did they chose to feature it on a show aimed at the general population?
The last "experiment" I wanted to mention is the low-carb diet intervention they carried out. Two GPs provided some patients to participant in a low-carb diet. The patients chosen were generally in larger bodies and had health problems such as diabetes, high blood glucose and risk of cardiovascular disease. We were repeatedly told that it was a lifestyle change, not a diet. Well I have news- IT WAS A DIET. To diet is to "restrict oneself to small amounts or special kinds of food in order to lose weight". So cutting out carbs with the aim of losing weight=a diet. (P.S. if anyone ever says it isn't a diet, it's a lifestyle change- it's probably a diet!).
Some key things to mention about this intervention:
We didn't find out what information the patients were given (or if they were given any other incentives), or whether they had access to nutrition professionals etc.
We followed up with the patients after two weeks and were told many of them had lost weight and some of them had reversed their disease conditions or improved their blood glucose. Why was weight even mentioned if this was a lifestyle change? And how does this provide any indication of whether the intervention was successful? Two weeks is nothing- let's see how the patients are doing in a year, or better yet in 3 years. How can this be advertised as a success in reality? Just because improvements were observed in a short time frame, this may not remain the case. Surely, we should be searching for long-term answers. Having short lived health is not true health.
There was no control group or other intervention group- The patients could have seen improvements to their health for reasons other than the diet, maybe some started exercising or adhered to their medication during the 2 weeks. There should have been a group on the diet intervention and another not on it.
The patients had the huge motivation- they were on TV and their results were told on TV. And, these patients were hand chosen by their GP to participate- so were probably the most interested. The general population may not have the same results as these patients.
Only 10 patients were used- this sample size is tiny and not representative of the general population.
So what does this experiment tell us? Well, very little. It doesn't help most of us, it doesn't add to scientific knowledge, it didn't teach us anything. It was used to entertain and "prove" carbs are bad. It does nothing.
SO. MANY. TO. MENTION.
First up- sugar cubes!
The dietitian had foods laid out on a table and had pairs guess how many cubes of sugar were in each food. Now what she was trying to discuss was the effect of carbohydrates on BLOOD SUGAR. Starch (the type of carb in bread, rice, pasta and potatoes) is basically lots of sugar molecules stuck together, so to digest it your body just cuts it up into sugars (glucose), which your cells can use for energy. Therefore, eating starchy foods does increase our blood glucose. But this has to happen for the glucose to get around to all our cells- our blood is our transport network.
What you need to know:
Glycaemic load is NOT the same as the sugar content of foods.
The foods used were set up to provide a "shock factor"- comparing a bagel and a chocolate muffin and stating the bagel has more sugar (it doesn't, by the way).
Mentioning only the sugar/starch content forgets so much of nutrition- the foods mentioned also contain vitamins, minerals, fibre, not to mention other factors that affect our foods choices, such as taste, cost, availability, ethnicity.
Next= the blood glucose test. When the intervention participants started, they were asked to consume a carb-loaded breakfast of toast, fruit'n'fibre, banana and orange juice. After consuming it they were asked to test their blood glucose and of course their blood glucose had shot up. One of the GPs commented "left untreated this can be dangerous".....
The thing is:
The breakfast was designed to cause a huge spike in glucose levels- it's full of carbs and sugar! It doesn't prove anything?!
Is this breakfast an accurate representation of what we normally eat in the morning? What I hear from people is "I have no time to eat in the morning", so I'm guessing most of us have some of those things for breakfast but probably not that much.
Yes, having very high or very low blood glucose can be dangerous if left untreated. However, these patients were under close care for the show. They were not in danger. Their blood glucose was not actually that high- this was manufactured by the meal.
Finally- we heard from a biologist about reproductive health. She claimed that diet is important for reproductive health, and an emphasis was put on carbs (of course). She stated that the "quality" of carbs mattered.
Problems with what she said:
We never found out HOW important diet actually is- I highly doubt it is as important as genetics, maternal health and a whole host of other factors. Perhaps the effect of nutrition is 50%, maybe it's 2%. Probably the latter.
What are quality carbs? Carbs are carbs. There are not good and bad quality carbs, there are just carbs. This statement was ambiguous and tells us nothing helpful.
The thing the annoyed me most=
At the end they presented some low-carb meals, most of which had veggies instead of carbs.
Lasagne with sliced aubergine instead of pasta...
Cauliflower instead of rice...
Key-lime pie with nuts instead of biscuits....
For me, it isn't lasagne without pasta, cauliflower will NEVER be rice and if you want dessert, have a proper dessert. Absolutely add veggies to your meals, but don't cut out other foods.
The show presented a highly biased view of carbohydrates and added to the misinformation regarding nutrition in the media, although it purported to provide truth. It is part of a string of TV shows claiming to help the public, while actually damaging us. I hope that in the future TV will take more responsibility for the messages it provides and will use appropriately trained professionals.
Please do not cut out carbohydrates or attempt to follow the "advice" provided in this show without speaking to a nutrition professional (registered nutritionist or registered dietitian).
Carbs are an excellent source of energy and other nutrients and should not be seen as "bad" or "good". All food has a place, as long as you like it!
Get in touch if you have any concerns about your diet or advice you've seen online or in the media. I offer free discovery sessions if you aren't sure how it works or want more information. If you are subscribed to my newsletter, you have a special offer sitting in your inbox for 121 counselling, and if you aren't well why not?! Sign up on my site!
Lots of love,
Little O x