Missed last night’s episode of the Catalyst? In the episode, Dr Maryanne Demasi asks international advocates, sports scientists and Australia’s leading nutritionists is the low carb diet just another fad or is there more to cutting the carbs? Read the highlights from the show that busts the low carb diet myths.
Dr Peter Brukner: LeBron James, Carmelo Anthony and Kobe Bryant are three of the biggest stars in American basketball, are now on low-carb eating.
Narrator: But is this just another fad?
Associate Professor Tim Crowe: What sells books is a new solution to our weight loss problems and carbohydrates are the perennial villain in this case.
Melanie McGrice: And a lot of these low-carbohydrate diets that people are following fad diets and people aren’t meeting all of their nutrition requirements. So that can actually be quite dangerous.
Associate Professor Tim Crowe: As a nutritionist, I’m willing to wear some of the blame here, that just that the simple ‘eat less fat’ message hasn’t worked very well. What happened was people ate less fat and replaced it with a lot of processed carbohydrates, particularly sugar.
Dr Peter Brukner: We’re all having far too many carbs, in our soft drinks, in our fruit juices. Processed foods is full of carbohydrates because when they took the fat out of food, they took the flavour out. So they had to replace it with something.
Professor Tim Noakes: What they deny is that humans have no requirement for carbohydrates.
Narrator: Controversially, some doctors are now proposing we flip the message. Instead of reducing fat, we need to reduce carbs.
Professor Tim Noakes: We’re just collecting information, we’re collecting the people.
Narration: South African Professor Tim Noakes believes the surge in carbohydrate consumption has contributed to the obesity epidemic. Why? Because carbohydrates stimulate a hormone called insulin, which increases the body’s fat stores.
Professor Tim Noakes: The role of insulin in the body is to build fat. So if you’re consistently eating every three hours carbohydrates, what happens is you consistently have an elevated insulin concentration in your blood. What that does is it drives the excess carbohydrate into the fat cells and the fat cells now cannot release the fat. The brain somehow interprets this as that you’re starving. So three hours later you have to go and eat again. And that is why you get this repetitive eating behaviour in people who are eating carbohydrates.
Narration: Of the three dietary macronutrients, carbohydrates are the most potent stimulator of insulin.
Professor Tim Noakes: When you eat fat, you get essentially no insulin response. When you eat protein, you get a moderate response. When you eat carbohydrates, you get relatively higher responses. Many people get the wrong impression of this diet. It’s not a high-protein diet for that very reason we don’t want all that insulin secretion from a high-protein intake. However, you do need enough protein to sustain your muscle mass and also to prevent hunger. But predominantly it’s a low-carbohydrate diet, that is the key.
Narrator: Professor Noakes says the low-carb diet with moderate amounts of protein helps you lose weight because it reduces cravings and makes you feel fuller for longer.
Professor Tim Noakes: What this diet does is it’s high in fat and protein and that satiates your brain and reduces your hunger. That is the key to this whole process because if you can reduce your hunger, your calorie consumption goes down.
Narrator: Spokesperson for the Dieticians Association of Australia, Melanie McGrice, agrees that a low-carb diet can help with weight loss.
Melanie McGrice: Somebody who I would consider putting onto a lower carbohydrate-higher fat diet might be somebody who needs to lose weight quickly, possibly if they’re going to have surgery or they might have been able to do exercise in the past, but now they’ve put on too much weight and they just need to get some fast weight loss off so that they can go and get back into exercise again. So there’s certainly times and places for a lower carbohydrate-higher fat diet. But what we need to remember is that that’s not a solution for everyone.
Narrator: While dietary carbohydrates are normally the main source of fuel in the body, they’re not an essential macronutrient. If you remove them from the diet, the body can switch to burning fat for energy instead.
Professor Tim Noakes: Humans have absolutely no requirement for carbohydrate, not one gram do we require. Whereas there are essential fats and essential proteins which we cannot generate in our body. We have this fabulous liver that produces as much glucose as you require.
Narrator: He says the optimal level of dietary carbohydrates will depend on how well your body processes them – some people metabolise them better than others. Low carb advocate, Dr Steve Phinney says many people are actually unaware that they’re ‘carbohydrate intolerant’.
Dr Steve Phinney: Carbohydrate intolerance is associated with some physical findings such as fat carried around the middle. It’s associated in people generally if they have a strong family history of type 2 diabetes, what we call pre-diabetes or metabolic syndrome, we have people who generally are severely overweight, and there’s some other conditions such as polycystic ovary syndrome in women, that is, they may not be overweight, they may not have diabetes, but is very responsive to carbohydrate restriction.
Narrator: Professor Tim Crowe, a nutritionist from Deakin University, is concerned that this diet will eliminate healthy food groups.
Associate Professor Tim Crowe: A very extreme low-carb diet can be quite restrictive. So it cuts out a lot of foods, particularly a lot of wholegrain foods. And even fruit, that has to be cut out as well. These are really good healthy foods that we know reduce the long-term risk of chronic disease.
Dr Steve Phinney: For many people, wholegrains are an excellent source of energy and a healthful food. But when people become more insulin resistant, they have a difficult time disposing off those carbohydrates. We’re not saying get rid of wholegrains in the diet, we’re just saying reducing them in the most vulnerable fraction of the population that can’t tolerate them.
Narrator: Low-carbohydrate diets are naturally higher in fat.
Dr Maryanne Demasi: We’ve been so conditioned to fear fat that making it a large component of your diet is hard to wrap your head around. It certainly was for Australian cricketer Shane Watson.
Shane Watson: Everyone that had educated me about the way to eat and eat a low-fat diet meant that I had a fat phobia. I cut all the fat off my chicken, my meat, my bacon, everything. So I stayed away from butter, from cheese, stayed away from nuts, only a little bit of avocado, all the foods that are high in fat and high in energy. But in the end I was always very hungry because I was cutting all the fat out of my diet and was just loading up on carbs. Within an hour of eating I was always very hungry.
Narrator: It took the personal experience of Australian Cricket Team doctor, Peter Brukner, to open Shane’s eyes to a new way of eating.
Dr Maryanne Demasi: Peter, how have Shane’s medical records changed since being on the diet?
Dr Peter Brukner: Shane’s always been one of these players who, despite high levels of exercise as an elite athlete, has always had a weight problem. Previously, the only way he could do it was really to starve himself. But since he’s gone onto this diet, he’s able to eat well, eat a large amount of saturated fat, his weight has been good. His skin folds, which is the way we measure the body fat – we measure that regularly in all the players – his skin folds have come down, so his body fat has come down. He’s maintained his muscle mass. So he’s also enjoying his food a lot more, he’s much less grumpy than he used to be when he was dieting, and generally I think it’s been a real positive thing as far as his wellbeing goes.
Shane Watson: My energy levels throughout the day have certainly improved, there’s no doubt. Leading into a break, like lunch or tea, I’m certainly not as hungry as what I was. So energy’s spread out really nicely throughout the whole day.
Dr Maryanne Demasi: When I first heard about restricting carbohydrates, Atkins Diet came to mind. How is this different to Atkins?
Dr Peter Brukner: Look, it’s fairly similar. Atkins was low-carbohydrate. Atkins probably didn’t emphasise the fat as much. So they probably had higher protein and not as much fat. I think the fat is really important. It’s sort of hard to get your head around the fact that, you know, the more fat you eat, the more fat you lose. That’s a very difficult paradigm. So there’s a lot of people out there who struggle with that.
Professor Tim Noakes: The only way this is slightly different from Atkins is we we promote vegetables. Atkins wasn’t really keen on vegetables, but his principles were the same – it was to cut out carbohydrates.
Dr Maryanne Demasi: Often when we hear about fat, it conjures up images of deep-fried chips and highly processed foods full of unhealthy trans fats. Well, this is different. It’s real food full of natural fats, like coconut, cheese, eggs and fatty meats, even good old-fashioned butter.
Narrator: Celebrity chef and vocal campaigner of low-carb diets, Pete Evans, says cooking with fat gets the best results.
Pete Evans: We know this, chefs know it – fat equals flavour. How good is that? We’ve got animal fat, and here we’ve got duck fat. But you could use beef tallow which is the fat from a cow. You could use lard, which is fat from a pig. You could use butter from the cow…
Dr Maryanne Demasi: All the things we’ve been told not to eat.
Pete Evans: Exactly. And my favourite, coconut oil, which is absolutely fantastic, great mono-unsaturated fat. And you can eat it by the spoonful.
Dr Maryanne Demasi: I see bone marrow and liver, these are rather old-fashioned cuts of meat. We tend to go for the lean steaks nowadays.
Pete Evans: Yeah, exactly. What’s interesting is our great-grandparents, they would’ve been eating marrow, heart, liver, brains, all of that because nothing ever used to go to waste. Because No.1, it’s cheap. No.2, it’s absolutely delicious and No.3, it’s the most nutritious part of the animal that we can work with.
Narrator: When restricting dietary carbs, people end up eating more fat, often saturated fat, which as been implicated in the development of heart disease.
Shane Watson: The first question I asked him was what about my arteries? Aren’t I just gonna…? Isn’t that fat that I’m eating just gonna go straight up and clog my arteries? And he made it very clear that that certainly wasn’t the case.
Dr Maryanne Demasi: One of the concerns is that the diet is high in saturated fat which we’re told raises cholesterol and causes heart disease. Are you concerned about Shane’s cholesterol.
Dr Peter Brukner: Not particularly. In Shane’s case, the HDL cholesterol, the so-called good cholesterol, has gone up. The triglycerides, which I think are probably the most important component, they’re carbohydrate-driven, and they have not surprisingly gone down significantly. So I think he’s in much better situation now than he was prior to this diet.
Associate Professor Tim Crowe: All diets fail because they’re prescriptive and they go against our normal eating habits. And the more restrictive they are, the harder they are to follow. It’s really hard to give up bread, pasta, rice, things we really love. That’s what you have to say goodbye to in a low-carb diet. So most people, eventually they will start reverting back to their old lifestyles and they will be back to square one, ready to soak up the next fad diet that comes along.
Dr Maryanne Demasi: Now, we know there’s no one-size-fits-all approach when it comes to diet. However there is scientific evidence to suggest that a large proportion of the population with obesity or diabetes would benefit from restricting carbohydrates.
Dr Maryanne Demasi: What’s wrong with replacing carbohydrates with low GI carbohydrates?
Professor Katherine Samaras: Low GI carbohydrates just refer to how quickly the glucose is released into the bloodstream. But the load, the total amount of carbohydrates, still has to be dealt with. In diabetes research, we’re understanding more and more that you can wear out the pancreas by getting it to work extra hard. And so, in that regard, the load of the carbohydrate actually counts. The GI may actually just blunt the glucose excursion after people eat. But it’s still asking the pancreas to work extra hard. And so lowering the GI doesn’t necessarily make the best outcomes.
Dr Maryanne Demasi: So what would you say to people who think this is just a fad diet?
Shane Watson: I’d just say try it and see how much difference it makes to your life.
Dr Peter Brukner: To me ‘fad’ means non-scientific and there is plenty of science out there. Ultimately I have faith that my profession is a science and they will see the science and eventually come around to this way of thinking.
Melanie McGrice: I think it doesn’t matter which side of the fence you’re sitting on, whether you’re going to be following a low carbohydrate diet or a higher carbohydrate diet, one of the key message everybody agrees with is the fact that we should be following a diet that has non-processed foods and lots of whole foods.
