SPP: Along the same lines here, I was wondering your take on things like grass fed beef or wild cost salmon, do you think that if you stick to more organic naturally raised food products, protein sources, meats, is that going to in the end be healthier? Can you eat more of it say if you don’t eat grain fed cattle and things like that, is that…?
Dr. Walter Willett: We in reality don’t have much directive as it bear on that question, that’s something a lot of people ask, but I suspect that it’s not going to make much difference actually. Maybe a little bit difference with say grass fed beef compared to grain fed animals, but the grass fed beef are still going to be high in cholesterol, because actually the cholesterol comes from the lean part of the meat actually primarily. And that’s going to be just as high in grass fed animals or even higher because the fat content’s a little bit lower. And it may be there’s quite a bit of evidence so that it’s the haeme iron, the form of iron we get from red meat that is causing part of the problem also.
So I think the best thing to do is actually, whether if you’d like to have beef, the main thing is to have it in small amounts. And if we’re having it in small amounts I don’t think it really does make too much difference whether its grass fed or grain fed some of the environmental affects, actually maybe not quite important for our long term survival and well-being that certainly is an important consideration.
SPP: I wanted to take a step back to when you were talking about starches with potatoes and rice, etc. In your, I guess revised food pyramid, you have whole grains as being a very important block of that pyramid. Can you give some examples of how you should eat whole grains throughout the day how much you should eat? For example with lunch, what whole grain should be included to make sure that you’re getting enough whole grains for the day?
Dr. Walter Willett: Sure. As you say whole grains do turn out to be really important because the natural whole grain has not just a lot of fiber into but a lot of minerals and vitamins as well. And when we refine that grain we’re taking away the fiber, we’re taking away the majority of the minerals and vitamins. And so we really stripped the grain of its nutritional value and what’s left is the starch. And it’s become very apparent that that starch, just like sugar, actually has adverse metabolic effects. And particularly it’s a form of grain that’s been grinded up into a refined powder like a flower based product such as bread.
And that form of carbohydrates absorb very rapidly. It makes the blood sugar shoot up, creates a much larger demand for insulin production by the pancreas and in the long run that increases our risk for Type 2 Diabetes and heart disease and other conditions. So the form of the grain is very important and we should be looking for the whole grains. It’s not very hard to do that. The whole grains are a lot more available in stores than they were even 10 or 15 years ago. So that means instead of having white bread having whole grain bread. And it should say an ingredient list or is the first ingredient whole, either wheat or whole or something like that. You want to see that word whole there.
If you’re having rice it means having brown rice instead of white rice, if you’re having pasta or having whole grain pasta instead of white pasta. And I think that those are all pretty easy tradeoffs. So one tradeoff that’s not so easy is if there’s no such thing as a whole grain potato, and so potatoes what we eat is almost all starch. And that does have the same metabolic adverse affects as large amounts of white bread. So keeping potatoes really lowering the diet is another important thing to focus on. And there is no whole grain version of that unfortunately.
There’s no exact amount of whole grain that we can specify. The main thing is if you’re having grains or potatoes, really be converting those two whole grain forms and really trying to minimize the fine form of grains. And what many people find if they’re really just consuming whole grains, weight control becomes easier because that add a large amount of fibers, more satisfying, it stays in our stomach longer and leaves us less hungry between meals.
SPP: And another important aspect of weight control is obviously exercise and on your food pyramid it is the bottom block, which I find very interesting that that’s really one of the I guess first times that that’s been included. Now with exercise I mean times have definitely changed compared to people working in fields and factories, they used to get exercise throughout the entire day, and now most people sit behind desks or have jobs where they’re not getting as much exercise as those that work in the fields.
What does a normal person need to do to make sure that they get enough exercise in a day? What is your recommended amount and how we can, I guess as humans, make up for the fact that we’re now working more sedimentary jobs as opposed to the physical jobs that we used to in the past?
Dr. Walter Willett: Right that’s absolutely true. In the past we didn’t need to think about getting exercise because it was just an automatic part of what we had to do in our day-to-day activities. But now as you say most of our lives involve sitting or driving or watching television or otherwise relaxing in a chair. So we have to really make a conscious attempt to make sure we’ve got physical activity built into our everyday life.
And the amount is in general the more the better but it’s actually surprising how even a fairly small amount of exercise compared to someone working in the fields all day can still be very important for our health. And the amount of exercise, in fact our minimal amount we should be aiming for is about half an hour a day of moderate to vigorous activity. That means like walking fast, just walking slow, but walking fast or running or really being active enough to work up a sweat. And if you’re just walking, if walking is the only part of it then you need to probably walk about an hour a day to get the minimum amount of activity that we really need.
And more is better and also what we’re seeing is its risk too. Do not just aerobic kind of exercise where we walk fast enough to breathe a little faster and work up a little bit of sweat, but also to incorporate resistance training or muscle building kinds of activities into our daily or weekly pattern. And it’s impressive even three or four times a week of resistance training, that means like using elastic bands or weights to strengthen our muscles.
That’s very important as well. In part that’s one way of getting upper body exercise that we otherwise don’t very often get. But using those muscles and strengthening those muscles actually means that the muscles take up blood glucose more effectively and reduce our need for insulin secretion. And so really amazingly just you can see it within hours of being physically actively. Metabolically we’re better off because our muscles are taking up the glucose and reducing our need for insulin. So the important part is to be building into our daily life almost every day some form of physical activity and trying to at least three or four times a week incorporate resistance training as well.
SPP: I actually wanted to really quickly, I know we’re running out of time here, but I wanted to ask you a few questions about things that are very prevalent today in the news. People hear a lot about and I think we can get confused about or I’m not sure what advice to follow. The first thing I was wondering was basically I’ve been hearing a lot about antioxidants these days, drink Pomegranate juice, drink green tea. I wanted to know if you had any insight on why there’s a big push for antioxidants and is this push valid. Does science and research back it?
Dr. Walter Willett: Right that antioxidant area’s been very challenging scientifically to get clear answers on that and that’s I think probably one of the most important reason for some confusion in the general public because people here from little piece of science of antioxidants are important. And the study may come out and be no and not show anything. Part of the reason is that these long term affects of antioxidants are very difficult to stud. They are almost very surely important because are metabolism just in functioning on a day-to-day basis creates a lot of oxidative stress. And the body has a whole complex system of antioxidant defenses to dampen down damage from that oxidative stress.
And that may be one of the reasons why we have so many redundant systems even from protecting us from oxidative damage that it may be that adding some more from Pomegranate or supplements, or something like that, may not make a huge difference because this is so important we already have a lot of built in defenses from oxidative stress. But there is some evidence that oxidative antioxidants can be helpful.
One of the best examples comes from the Physician’s Health Study Trial where over 22,000 men were randomized for, to either beta carotene pills or placebo and there was no change in heart disease or cancer, but after 18 years the men on beta carotene actually had better cognitive function. And that’s really I think a very important finding because it took 18 years for that benefit to show up.
There was no other study that’s been that long, which I think is telling us that many of the studies that have been conducted are certified value, they just haven’t gone on for long enough to see that sort of modest but important cumulative effects of benefits of antioxidants. And it was a first direct effect, a first direct demonstration that antioxidants can be beneficial for protecting the brain from the decline in cognitive function that’s typical with aging.
And so I don’t think that that study means that we should start taking beta carotene pills but it does mean I think that we should make sure our diet does include lots of fruits and vegetables, particularly our dark green leafy vegetables and orange vegetables like carrots that are a good source of beta carotene. We don’t want to be short on that.
So I think the general evidence doesn’t suggest taking pills necessarily, but making sure we eat a diet that does have lots of antioxidants in it. I’m not so much a fan of Pomegranate juice because most of that has a good bit of sugar added in and that probably outweighs any benefit. But having the Pomegranate, having a variety of vegetables, particularly green leafy vegetables, dark orange vegetables, is an important part of everyday healthy diet.
SPP: Okay that’s good to know, maybe clear up a little bit. Also you mentioned weight lifting how that can be very important. And I know that growing up doing a lot of weight lifting I was kind of pushed towards doing protein supplementation, what almost seemed like overconsumption of protein through powders and bars and things like that. Do you have any stance on if that protein, the amount of protein recommended, is necessary and if overconsumption can cause damage, especially through the methods that are available, such as powders and drinks and such?
Dr. Walter Willett: I don’t think there’s any good evidence that those really make very much difference. It’s really actually the physical exercise itself that really helps build up strength. If we were really protein deficient the supplements might help but very few Americans are actually protein deficient if you’re having a variety of every diet with some combination of meat or eggs or dairy products or beans and nuts and whole grains. You’re going to get enough protein and adding protein supplements on top of that is very unlikely to have much additional benefit.
Now if those supplements are really proteins it’s probably not going to be harmful and it’s taking in huge amounts. But you really need to be careful because a lot of the supplements out there do contain hormones in them that can have adverse affects. And so I think it’s really better again to go like get our protein from food. Again the protein doesn’t come in isolation it comes as a package where fat and you’ll want to have protein sources that have healthy fats, which tend to be the vegetable sources of protein and fish. And we get other minerals and vitamins when we eat those protein sources as foods that we don’t get those necessarily taking protein supplements.
So the bottom line is you can be absolutely healthy and strong and you don’t need to take protein supplements.
SPP: Okay great. Alright well I guess in summation for us and maybe for our listeners who haven’t had a chance to read your book or have seen the food pyramid recommendation that you have, could you give a quick synopsis of how you believe we should be eating today and just a general idea of how to be healthier through the food that we use?
Dr. Walter Willett: Sure. It’s really not too complicated and just describing our pyramid for those who don’t have it in front of them right at the base. As you mentioned we put regular exercise, physical activity, and weight control because that really is important and almost all of us need to slip old physical activity into our daily life. I would add, by the way, it doesn’t necessarily mean going to the gym you can build it into the way you get to work. I ride my bike to work every day so I automatically get half an hour of physical activity right there that does make a difference. I try to put more on top of that but that’s a good base.
Then the next level of our pyramid we really put side-by-side whole grains and healthy fats and that’s out of the reality that everyone is going to get the vast majority of their calories from some combination of carbohydrates and fat, and while receiving this it doesn’t matter exactly what that percentage is or percentage of fat or calories of fat or carbohydrate, what’s really important that we get some combination and that there be healthy forms of carbohydrate the whole grains or healthy fats, which are mainly the vegetable plant oils.
Then at the next level we put fruits and vegetables and we should be consuming those in abundance. But we did not put fruit juice in there quite specifically because it’s way too easy to get an overdose of sugar from even a 100% natural fruit juices. We should be consuming them in small amounts if at all. We really should be consuming fruits as whole fruits.
Then at the next level we put vegetable sources of protein, beans including soy products, and nuts. Those really have a lot of positive health value and if you want to be a vegetarian you can get all your protein that way, but if you want to be an omnivore it’s good to have some of those. And then you can also have some protein from fish, from poultry, small amounts from eggs as well. And especially the fish are good to include because they are a good source of Omega 3 Fatty Acids.
Then at the next level we put dairy products and that’s most complicated area because there are some good nutrients in dairy products but we see that overconsumption like three servings a day as recommended by the US Food Guide Tournament is really too much. We see that men have higher risks of fatal prostate cancer with the equivalent of three glasses of milk a day either as milk or as cheese. And that’s an overdose of dairy products. But if you have one or maybe two, sometimes two servings of dairy products, that seem to be okay, but you don’t really need to have any. In fact most of the world doesn’t consume dairy products you can get enough calcium from otherwise a healthy diet.
Then up at the top we put the foods to use sparingly. And that doesn’t mean you have to totally eliminate them if you like them a lot you can have them but have them now and then not on an everyday basis. And that would be foods like red meat and butter, which do have a lot of saturated fat and cholesterol in them. But even more importantly up there at the top we put refine starches and sugar with the white bread, white pasta, white rice, sweets made out of sugar, and especially sodas and every other sugary beverage.
Those foods actually most of them are at the base of the US Food Guide Pyramid, but those foods shave lots of empty calories in them and they lead to weight gain, diabetes, heart disease and don’t have positive health benefits. So those are things we really want to keep low in our diet. Unfortunately they are the single biggest source of calories in the mainstream American diet. And that’s probably the big amount of refined starch and sugar is probably now our Number 1 nutritional problem.
SPP: Thank you very much. I’m sure our listeners will be healthier after this, so we really appreciate you taking the time out of your busy day. I know you have a lot to do there in Harvard. But thank you so much and we’d like to reiterate to our listeners that Dr. Willett has a few books out. The most popular would be “Eat, Drink and Be Healthy”, which is a great book that we recommend everybody pick up to help them live a healthier life.
Dr. Walter Willett: Thank you very much and good to talk to you. SPP: All right thank you.
SPP: Thank you so much.
Dr. Walter Willett: Bye.
Smart People Podcast, Episode 1 – Dr. Walter Willett on Nutrition