Les États-Unis devancent souvent l’Europe dans les technologies les plus avancées, mais également dans les modes de vie malsains. L’UE pourrait donc se tourner vers les États-Unis afin de trouver des solutions à l’obésité, a déclaré James O. Hill.
James O. Hill est professeur de pédiatrie et de médecine et le directeur général fondateur de l’Anschutz Health and Wellness Center au Anschutz Medical Campus de l’université du Colorado. Il est cofondateur d’America On the Move et membre de l’Expert Panel on Obesity of the National Institutes of Health qui a mis au point les première lignes directrices américaines pour le traitement et la prévention de l’obésité. Il s’est confié à Henriette Jacobsen d’EURACTIV.
You have been speaking today in Britain on obesity, what was your main message?
Well, I had a couple of messages. One is that we really need to think about a unified strategy and how to address the issue over the long term. What I think we have going on now is a lot of different tactics, but no real plan on how to address it.
Sometimes I get so frustrated because I see so much focus on food. Once you understand how the body regulates energy and body weight, physical activity is incredibly important and it’s not just burning calories. As you become physically active, your body changes and has a whole different way of handling food and fuel. So first thing is we got to understand that we can’t solve this problem with food alone.
The second thing is, the way the body prefers to achieve energy balance and a stable bodyweight is through a lot of calories coming in and a lot of calories going out. That may sound very funny, but if you look back traditionally as a species, we have always had to be physically active. It has only been the past few years that we have actually been able to afford to be sedentary, so our physiology works best when we burn a lot of energy and we eat a lot.
Our brain tells us to eat all the time so we are very good at eating and we are very poor at food restriction. So that situation is when you are very physically active and you eat a lot. That’s sort of where we were during most of our history. What we are trying to do now is we are trying to be sedentary and not using much energy and we’re trying to food restrict to match that low level of expenditure and we’re not very good restrictors because our bodies regulate our appetite so well, when we food restrict, we get hungry.
The way our body handles this issue is when we gain weight and become obese and the process of becoming obese increases our energy expenditure so we get back to that level of a lot of energy out and a lot of energy in.
Your last point, is it related to what you call the ‘energy gap’?
The ‘energy gap’ is the degree of behaviour change we’re going to need to be able to solve our problem. If we look at what it takes to stop weight gain in the population, we have estimated that’s pretty small; less than 100 calories a day. If we change our behaviour by 100 calories a day which means eating less or moving more, a combination, then that’s not a lot. We can do that with small changes. We can totally stop gaining weight so that our obesity rates would never go any higher.
When we start talking about treating obesity, that energy gap is higher. Once you are obese, it’s always going to be harder to maintain your weight. So if you want to lose 10-15% of your body weight and keep it off, you are going to have to change your behaviour by 200-300 calories. That’s the concept of the energy gap. It means that it’s going to be far easier to prevent obesity than to treat it once it’s there.
For someone who is obese, what is the best advice in order to lose weight?
I think there are lots of ways to lose weight. We lose weight by eating less, but that’s a temporary period. We see that treating obesity is consisting of two phases.
The first phase is weight loss. You can do that through a lot of different ways. You can choose any diet in the bookstore, but the harder part is phase two which is keeping weight off.
When we study what it takes to keep weight off, we find there are not a lot of ways to do it. There are much more similarities in how people succeed. It starts with a high level of physical activity. You don’t need to exercise to lose weight. You can lose a lot of weight pretty easily with absolutely no exercise. But if you want to keep weight off, exercise becomes the key factor in terms of doing that.
The second thing is that we find is that the people who are successful eat a low-fat, low-calorie diet. They watch what they eat, they use sweeteners instead of sugar, they look for low-fat options. They learn to be really smart eaters. They are very consistent and get their exercise every day, they pay attention to their diet every day, they eat breakfast every day and they report their work periodically so that they make sure they are doing OK.
The easy part is weight loss. Lots of people succeed in losing weight. Most people who lose weight regain it.
What can Europe learn from the US when it comes to obesity?
The most important thing you can learn from us is what not to do. First of all, food restriction does not work. We have been promoting food restrictions for decades. It does not work. People will skip their food intake, they get hungry and begin eating again. So food restriction is not a long-term solution.
Often we hear people say, “To lose weight, you have to move more and eat less”. I think that’s the wrong message. You have to move more and eat smarter. So if we were able to in a population, either the US or Britain, to raise the physical activity level, I’m talking about 30 minutes of movement every day, then you don’t have to food restrict to maintain a healthy weight.
Then we look at eating smarter. What does eating smarter look like? It looks like watching you portion size, reducing your energy density which means foods that are lower in sugar and fat and using low-fat products. What we know from the science is that when you eat that way, you automatically eat less. So you are not hungry. You are actually fuller on less calories.
Increasing physical activity with eating smarter is going to give people a better chance of maintaining a healthy weight.
If you are already overweight, you got to get that weight off, so you got to go through a dieting period, but keeping that weight off, involves those two things.
During the financial crisis we have seen that prices on food have gone up and the least expensive food products are now also the unhealthiest ones. The crisis has sort of giving people a reason to buy fattening food. How can we reverse this trend?
This is the issue. People say, “You tell me to eat healthier, but it costs more to eat healthier”. One of the things we found that you can do is… Healthier food actually becomes more affordable when you cook it yourself. Part of the issue in the US is that people forgot how to cook. Often the most healthy food costs a little bit more in the grocery store, but if you cook it yourself, you can eat healthier on a budget than eating out.
I think teaching people how to cook things again and how to use flavours… We use a lot of sugar and fat, but spices and flavouring can make up for a lot of that.
In Denmark, the government put a tax on food with saturated fats, but they had to scrap the tax after a year only because too many people did cross-border shopping in the neighbouring countries in Germany and Sweden. What do you think of putting taxes on certain foods to combat obesity?
Taxing foods as a strategy as some people have proposed… I’m very sceptical myself that that’s going to work. Part of the problem is I think it’s difficult to focus on food as good or bad. It depends on what you tax, and I think as we saw in that example that people are going to find ways around it.
I think we absolutely need to work with the food industry to develop better products. I think the food industry does have some responsibility. I think we should ask them to help with reformulation in marketing healthier products. We also have to educate people on how to make better choices.
We sometimes confuse people; this week sugar is bad and the next week fat is bad. This is a complex issue, but I think it can be communicated to the public in a way so that they understand what to do and underline that none of this is going to work if the population can’t get moving more.
At the moment, we see that many countries are cutting costs within their healthcare system and most of these cuts are in the area of prevention. How do you think this will have an impact on obesity rates in the future?
I think it’s just the wrong way to go about it. You see that in the US we waited until people started experiencing all these consequences of obesity and then we paid for their healthcare when in fact if we had invested money in keeping them healthy, they wouldn’t get these conditions and it would save us a lot of money.
The problem is that investing money in prevention is going to pay off way down the road instead of right away. But we can’t go on simply treating the consequences of obesity. At some point we have to wake up and realise, the way to handle this issue is to work on keeping people healthy and not letting them get obese in the first place.
Some researchers are saying that we shouldn’t measure obesity with the BMI number. Instead, we should be measuring people’s waistlines. What do you think of measuring obesity this way?
I don’t think it matters. BMI is not perfect, but it’s pretty good for calculation measures. Waist measurement is also pretty good. I tend to favour BMI. It’s not a perfect measure, but I think it’s pretty good for what we need to do. Measuring waist is good as well. In the best of circumstances, we measure both.
People say, “Don’t measure my BMI because I have a lot of muscles”. This is where if you measure both BMI and the waistline, those people that have extra muscles will have a high BMI and a low waist number. If you have a high BMI and a high waist number, you can be pretty sure that it’s not extra muscles.
What can a supranational organisation like the EU do to fight obesity?
That’s a great question and it starts with committing to research. At the end of the day, we got to base our interventions on good science and we need a lot more good science surrounding behaviour change, prevention and treatment.
But the other thing that I think is going to be important for something like the EU to do is to say we need to bring everybody together on this. In particularly we need academic experts, we need people from the governments and people from the industry. I’m not talking just about the food industry.
There are a lot of industries that make money from people being sedentary, selling you big screen TVs, automobiles and everything else. I think we have to engage them, not to blame them, but to be part of the solution. We can develop the best program possible via academics, but we don’t do so well marketing that. This is where we need the industry with us, seated at the table and we need them to marketing healthy lifestyles and products to the population.
Countries that recognise this and bring everybody together to say we need to combine all of our expertise to first of all decide what people need to do and second, to market that to people where we live; in the grocery stores, restaurants, parks, I think that is what it's going to take to reverse this epidemic.