On Friday, 28 May I visited Dr Manny Noakes, Senior Dietitian and Research Scientist at the CSIRO Health Sciences and Nutrition in Adelaide, South Australia to talk about the latest research on the weight loss and health aspects of higher protein diets.

Here's the interview - it's long, but very informative!

Matt:
I'm speaking with Dr Manny Nokes at the CSIRO in Adelaide. My name is Matt O'Neill. Welcome Manny. Thank you very much for your time today.

Manny:
Pleasure Matt.

Matt:
You've been researching higher protein diets and their impact on health and weight loss. How did you get interested in it and what did you try and find out?

Manny:
Probably because a lot of people were asking us what is the best dietary pattern and we have a lot of volunteers that go through our clinical research unit. Weight control was a big topic for them.

Because we are a nutrition research organisation they thought we would know all the answers and when we looked the literature to find out whether we could find those answers for them we realised that there was very little in this area.

There had been a little bit of work done in isolated cases but really in terms of the questions we were being asked there was really no answer and so we thought this was a good opportunity to do some research and see whether a high protein pattern makes any difference at all in terms of weight loss or appetite control or any metabolic effects.

Matt:
So this really came from the people in the clinics wanting weight loss. So the CSIRO being a big research organisation had the clinic and people were asking, so you said well lets try and find out.

Manny:
We weren't doing projects on weight loss at the time, but it seemed a topic that everyone was interested in. We thought that the CSIRO is meant to be serving the community and the consumer so we had the opportunity to do it. We thought it was an important thing to be doing. And certainly I'm even more convinced of that now as I see the obesity problem becoming worse and we're going to need a lot of community support systems for people who need weight control. We need the best advice to help those people provide those support systems.

Matt:
And how did you set up the research project? What was the hypothesis or what you were trying to find out?

Manny:
Our original hypothesis was that there would be no difference between high protein patterns and high carbohydrate patterns in terms of weight loss.

Matt:
What would you classify as a high protein diet and low-carbohydrate?

Manny:
High protein can be as high as you like. We opted to look at more moderate protein intakes that were more consistent with what people could eat and we looked at patterns that were around the 100 grams of protein a day, which were in effect around 30% of calories from protein a day. That's less than some of the very low carbohydrate diets that are available in the community.

Matt:
And for low-carbohydrate? When you hear that term, how would you classify low-carbohydrate?

Manny:
Low-carb is by definition is generally less than 100 grams of carbohydrate per day. Less than 60 grams is getting into the ketogenic area and an Atkins type diet in the induction phase is less than 20 grams of carbohydrate. The high protein, low carbohydrate pattern we are interested in is around 160 grams of carbohydrate, so it's not extremely low-carb. Its moderately low-carb.

Matt:
So you are comparing one group that had a higher protein say around 100 grams or so, about 30% protein, with a conventional diet?

Manny:
With a high carbohydrate pattern. We kept fat the same because we were asking the question, if you switch protein for carbohydrate, keeping fat the same, what happens to weight, body fat distribution, cholesterol levels and other parameters of health.

Matt:
And with weight and shape, how long was it and what happened?

Manny:
We started off with a sixteen-week study. We did 12 weeks weight loss and 4 weeks weight maintenance and we've done that in about three to four studies now, and in each case we saw benefits with the higher protein pattern. Not that it was a massive effect because we kept the calories very similar with both dietary patterns.

But we did see that people lost more body fat and preserved more lean mass and in one of the more recent studies we did in women we saw that there was a real benefit for people who had elements of metabolic syndrome.

So if you had high levels of triglycerides you lost a lot more weight on the high protein patterns compared to the high carbohydrate pattern, which is totally unexpected because we hadn't actually seen that before and it was the first time that we had appreciated that depending on your phenotype you might need a different dietary approach.

Matt:
And by phenotype you mean?

Manny:
Yes, its not so much your genotype, because its hard to define what ones genetic traits are, but a phenotype is either appearance of someone in physical stature or their biochemical characteristics. A high triglyceride level is a biochemical characteristic which is part of a group of characteristics that defines what we call the metabolic syndrome. If you're in that group you seem to do better on less carbohydrate and more protein.

Matt:
This has also been called Syndrome X. Cholesterol, blood pressure and the things that go with it.

Manny:
Its got a number of features and you have to have three of them to be classified as having Syndrome X. But a high triglyceride is one of the easiest things that can be measured. And its one of the distinguishing features as well as a large waist circumference.

So that was interesting because there is always a lot of hype about different diets for different people based on blood type and that's never had any rationale basis, but we have been finding that depending on any certain physical characteristics and biochemical characteristics there may be dietary patterns that people do better on both from a physiological point of view.

People on a high protein pattern with syndrome X tended to have a better outcome in terms of triglyceride reduction and they also have a better outcome in terms of body fat.

Matt:
So that could mean that if you knew somebody, they walked in the door to the clinic at a certain weight, you may say you're overweight, but before you knew what sort of diet they would do best on you'd want to know about their triglycerides or other factors.

Manny:
Sure, you'd want to know those things, but to be fair though you'd also want to know what their food preferences are. You can suggest to someone that the best diet for them is high protein because they've got Syndrome X for example but if they are people who really don't like high protein foods they may not cope with it, so you are going to improve your health by losing weight one way or another.

The important thing is to find, (a) the diet that is best metabolically and (b) the diet that is best from a behavioural point of view that people can cope with.

Matt:
How many people in your study did it tough or found it difficult having to eat higher protein?

Manny:
Probably a smaller number than I thought actually because the women in our last study, and we had 120 of them, probably 10 percent that didn't cope with it particularly well, but in large the majority did.

Mind you the people on the high carbohydrate diet did ok. But because that was more like what they'd normally been told to do they didn't seem to like it as much and more people dropped out of that pattern than the high protein pattern. So that was a bit of a surprise. We thought that women wouldn't like a lot of red meat, a lot of dairy, etcetera. But the opposite was the case. They seemed to cope really well on it and found it quite sustaining.

Matt:
One thing that has been claimed for a higher protein diet is the satiety affect, or making you feel full. What feedback did you get from the study subjects in this area?

Manny:
Yes, in the higher protein pattern we've done assessments of satiety and in general the high protein pattern seemed to be better tolerated because they do seem to subjectively make people feel somewhat more satisfied. The effect is relatively subtle. But when you are dieting you do get hungry, so if you can avoid those pangs of hunger by eating protein at each of your meals that can be of benefit.

Matt:
Was this something that thirty years ago Dr Atkins, with the Atkins Diet knew this, that higher protein diets could make you feel full.

But he didn't seem to get much support from the scientific community at the time. That's not to say that his low-carbohydrate diet is the way to go, but are there any positives from back then, and were their any risks with the Atkins Diet thirty years ago.

Manny:
Well he knew that it worked, but I don't think he really knew that it was because of protein. What he understood was that ketones were the key factors that made people feel not hungry and that you would produce ketones when you are losing weight on a very low carbohydrate diet. And certainly ketones can supress the appetite. But in fact the real reason was probably related to the level of protein in that dietary pattern. I don't think he really appreciated why the diet was working nor did he appreciate that you didn't necessarily have to go as low carbohydrate as he was suggesting.

If you look at the diet in the induction phase its certainly nutritionally inadequate, not that that's a major problem if you are only doing it for a short period of time but it isn't something that is sustainable.

We've done studies at the CSIRO on the Atkin's Diet compared to conventional dietary patterns and people cope with it and you do lose a little bit more weight, but when we measured where that weight loss was coming from we found that the amount of fat loss was the same, but there was a little extra muscle loss on the Atkins pattern. So some carbohydrate is important for retaining lean muscle mass. You do need protein for lean muscle mass, but you also need carbohydrate to preserve it as well.

Matt:
Is the carbohydrate then, providing enough energy so the body doesn't go looking for alternative fuel sources, which in effect is muscle and this can have a negative affect on your metabolism.

Manny:
Primarily the Atkins Diet relied on the notion that you could eat as much protein and fat as you like as long as you avoid carbohydrate, and that you could eat more calories and lose weight than you could on another diet, and that notion is not true.

Basically when people go on an Atkins' Diet they eat less. They don't realise they are eating less because eating less is less difficult. And I think that is an important feature of a high protein pattern that you can eat less and feel comfortable doing so. That isn't always true of very high carbohydrate patterns.

Matt:
The criticism for the Atkins Diet which is the high saturated fat intake that leads to high cholesterol and therefore health risk. How do claims of this compare to what you've been looking at?

Manny:
We looked at what happens to cholesterol, but of course if you measure cholesterol levels while you are losing weight your cholesterol levels go down because you are in active energy restriction and you have less cholesterol synthesis. So if you are in active energy restriction it looks good. As soon as you stop losing weight your cholesterol shoots up and we've shown this on the Atkins Diet at studies at the CSIRO.

If you lose enough weight you can get your cholesterol down on Atkins, but it won't go down much, and for some people it will go up. However, there are a lot of other benefits of losing weight on Atkins too, which we have to be aware of and that is if you have got very high triglycerides your triglycerides go down very quickly, your insulin levels go down quickly and your blood sugar levels go down quickly.

So there are benefits of lower carbohydrate patterns. Its just that you can't sustain that level of carbohydrate restriction, so less carbohydrate is helpful as is more protein and finding a balance between those two macronutrients is what we've tried to achieve in the CSIRO Total Wellbeing Diet.

A pattern that is nutritionally sustainable, is adequate and has the benefits of protein from an appetite regulation point of view but doesn't cut out carbohydrate from the point of view of muscle preservation and from the point of view of a lot of the micronutrients that you get from whole grain foods as well, and in terms of bowel function.

Matt:
It sounds like it's attempting to take the best things from what we know of a range of diets and put them into the one diet. You mentioned bowel function. Any research ongoing there to see if there are any other health risks? And before this sort of approach was adopted people would say, “What about the unknown risks?” Did you check on those?

Manny:
We do need to be aware of those and the CSIRO in Adelaide at Health Science and Nutrition has the capacity to explore bowel health as well as cardiovascular health and we are engaging in a study to look at the effects on bowel function. We have done studies in the past on weight loss and the effects on bowel and what we see with anyone losing weight, they become more constipated and so if you are losing weight on a low fibre pattern that's going to become even worse. If you persist with that pattern over a longer period of time what the impact on your bowel in the longer term? We are interested in that.

But are there any particular adverse effects of eating higher protein foods, particularly eating more meat on bowel health, when you are losing weight? That's an important question. The evidence at the moment is that obesity and lack of exercise is one of the key risk factors for colon cancer, more than any particular food component.

So, if someone loses weight on a higher protein pattern then they are going to be better off from a bowel health point of view. But we want to confirm that in some studies with humans to actually demonstrate that that is actually the case.

The whole issue of insulin resistance which is the key feature of being overweight for many people also impacts on many other diseases like cancer and we don't always appreciate how being overweight and obesity impacts on other health aspects apart from heart disease.

It really is quite powerful, so losing weight can have amazing benefits, more so than a lot of the drugs, and we have some very powerful cholesterol lowering drugs. But 4-5 kilograms of weight loss can do so much more than many of those drugs. I think that this is something that as a community we should be aware of even if we don't lose vast amounts of weight, small amounts of weight loss can be of enormous benefit.

Matt::
With the health community promoting a moderate weight loss, or a small amount, maybe just 10% of your weight, or 10kgs or so, and having enormous benefits, plus words like insulin and glucose and the difficulty of communicating that quite clearly, who do you think are the implications of this low carbohydrate craze that has hit the United States? What do you predict will happen here, how will the industry react and what should we be trying to do to help Australians in the community?

Manny:
I think industry is thinking very carefully about going down the low-carb route and I probably think there is some consumer demand. I think we have learnt a lot from low fat to know that if we start to develop a lot of low-carb foods we'll have the same scenario as we did with low fat.

Low fat was a great message when low fat meant restricting a lot of high fat foods and not replacing them with high-calorie, low-fat foods, which is what's happening now. The same thing is going to happen if we have a lot of low-carb foods, as we probably haven't been better off with low-fat foods.

If we completely forget the message that calories count then we will be no better off with low-carb foods as we probably haven't been better off with low-fat foods. So what I'd like to see is more emphasis on lower kilojoule foods that are satisfying rather than low-carb or anything else. High protein fine as long as they are low-kilojoule.

Focussing on kilojoules is likely to be a more responsible way to go and certainly more responsible for the food industry in terms of product development.

Matt:
There was a journalist recently in USA Today who wrote a comment as a journalist, not as a nutritionist. He said in the good old days when Atkins was around, if you were going to eat low carb, to be still healthy you had to restrict what you eat. He was talking about low-carb junk food. High protein low-carb foods that were now processed and didn't have that much else in them in the way of nutrition. And this raised the question of how you have a healthy diet. On one hand you have a lot of food choice, but on the other hand you could eat less nutritious foods. Do you think that will happen and how do we prevent that from happening?

Manny:
One of the big problems is that we have far too much choice and maybe that dietary guideline of eating a variety of foods isn't such a great one because we've got more variety than we can poke a stick at. We know from research that if you increase variety that people have exposure to and they will actually eat more. So variety is bad news.

I think we are seeing a huge change in the way we look at food at the moment because of the obesity problem. Every day we hear about it in the media and the food industry is absolutely concerned, the public is absolutely concerned, the government is absolutely concerned and I think we'll see a radical shift in the role nutrition plays in food product development and I hope that the direction that goes will be in a way that is consistent with good health.

And so new foods need to be developed that have less calories, that are portion controlled and are more nutritious. So just less calories alone isn't going to be that helpful. I think we have to consider nutrition and nutrients and the old fashioned issue of nutrition is going to come back on the agenda.

I have to say groups like McDonalds starting to change the oils that they cook their foods in and they are starting to introduce salads. You know, the community is ready for that and I think that anyone can criticise McDonalds for not having done that earlier, but I think the community has to take responsibility for the fact that had they done it earlier, they probably wouldn't have been successful. Now is the right time and I hope that a lot of other fast food companies will follow suit because we not going to be cooking a lot more food in the future. We'll be relying on food companies and various outlets to provide our food, ready made. And there's nothing wrong with that as long as those foods are nutritious and not high in kilojoules.

Matt:
Does this mean we are on the virge of something really positive in terms of nutrition? You often hear the fruit and vegetable growers say that the processed food industry spends in one day more money than they do in a year on advertising. Is this going to mean that for McDonalds and other big players due to convenience, we're going to see nutritious food become healthy and funky or sexy and a fun thing to have?

Manny:
Absolutely, I mean I think that's what McDonalds have done in a way and say that nutrition is an issue and nutrition is popular and as you say, its fun and funky and that is a huge cultural shift.
Because up until now nutrition has been a bit kind of greeny and a bit fringy, and so what we're seeing is a cultural shift in how we look at our food and to look at our food from health rather than just convenience and enjoyment. Not that those two things necessarily need to go away, but I think nutrition has to come up as part of that triad as well.

Matt:
Coming right back to the individual as part of our final discussion. If an individual says I look a bit podgy as they walk past the mirror in the morning, and say I must do something about my weight, exercise aside at this stage, for there diet where should they start. What is the best advice?

Manny:
Gosh, that's a really big question and it depends where you are a DIY person or whether you need support, and lets face it, a lot of people need support and that's certainly our experience from all the clinical trials we've done at CSIRO. Support is important and there are a lot of emerging community support systems. And there are groups like Weight Watchers do an excellent job. They there are groups like Jenny Craig and Lite & Easy that are doing a good job too. But I guess at the end of the day you have to be self-reliant and CSIRO is providing information to people who want to do it themselves. At least develop a diet that we can put our hands on our heart and say we've tested it, it works well, its good for you. If you really want to change what you're eating then have a look at this and try to approach that as a benchmark for what a healthy eating might look like.

Alternatively, going to see a weight loss counsellor or dietitian is important and having that kind of connection with someone who can advise you, because there are a lot of options with dietary approaches. I think that can be an important part of the future and I think in the future there is a huge market for having community weight loss support systems available for people.

Matt:
So if someone was thinking about trying the extreme low-carbohydrate, high protein diet, and you met him or her in the supermarket, what would be the quick thing you'd tell him or her?

Manny:
I'd say look, I know you're motivated and because you're motivated you'll be able to do this for a while and it will work OK, but remember that in four weeks time when you've had enough, there's another way. Don't throw the baby out with a bath water. Try something that is more in between and I'd say that because I know that high protein is very successful, the CSIRO Total Wellbeing pattern is one that they can at least rely on.

So when people are motivated I don't try to say don't do it, because motivation is so hard to get. And that's what people are looking for. Don't squash that, but just say, “When you've done that, that's OK. You won't come to any harm in the short term. But don't follow it long term, and I know you won't be able to anyway. There is another alternative and this as a step in the right direction.

Matt:
It sounds like that if people were prepared to do a bit of trial and error about the best diet for them, rather than get stuck on someone else's diet. If they new they we finding out their best way they would be more successful. But that's so hard to convince people of.

Manny:
I think you can do a lot of personalising from what you can see of diet plans. You can pick and choose. For some people can go about it in a qualitative way I know that some blokes are good at “I'll drink less beer.”

Other people prefer something that's much more concrete, particularly women who are very organised and meticulous. Prefer to have a structure of breakfast, lunch and dinner. I was astounded at the success the CSIRO Diet got when it was in the newspaper. We put out meal plans with a structure of breakfast, lunch and dinner and I was astounded at the success the CSIRO diet got I the newspaper when we put out meal plans. It was like they forgot the structure of the diet. It was the meal plans that got them in.

And I guess we have to accept that people may not know what to eat every day and making decisions about food can be hard, so having some sensible meal plans it gave people a way of picking things they liked out of that to structure their own dietary pattern.

Matt:
If a client was saying, just give me something to stick to, are you saying give that to them and then over time broaden food choice and learn that would be good.

Manny:
I think so, we have to listen to what people are saying they need instead of telling them what they need. If they are saying to us we need to know in a very concrete way what to eat for breakfast, lunch and dinner. And I think we need to paint that picture for them. And we do that with them inputting their food preferences and working that out.

I don't think that's a cop-out at all. I think that is part of a good quality service that someone can provide, because it's not something that comes naturally to many people anymore.

Matt:
Dr Manny Nokes, thankyou very much for your time today. This is certainly insightful and a lot of food for thought. I appreciate your time and look forward to hearing from you again.

Manny:
Thanks Matt. Thanks for the opportunity.

(C) Matt O'Neill & Manny Noakes, 2004

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CSIRO.com.au CSIRO's Health Sciences and Nutrition.