Author: Dr Mercola

Full article

According to a study published in 2013, nearly one in five US deaths is now associated with obesity^[1]. Obesity is indeed a marker for chronic and potentially deadly disease, but the underlying problem that links obesity to so many other serious health issues—including heart disease—ismetabolic dysfunction.

Mounting evidence clearly shows that added sugars, and processed fructose^[2] in particular, is a primary driver of metabolic dysfunction.

Refined fructose is actually broken down very much like alcohol^[3], damaging your liver and causing mitochondrial and metabolic dysfunction in the same way as ethanol and other toxins.

It also causes more severe metabolic dysfunction because it’s more readily metabolized into fat than any other sugar^[4]. The fact that refined fructose is far more harmful to your health than other sugars was recently highlighted in a meta-review published in the Mayo Clinic Proceedings.¹

The average American consumes one-third of a pound of sugar per day, half of which is processed fructose. Other statistics found in Dr. Richard Johnson’s book, The Sugar Fix,² suggest about 50 percent of Americans consume as much as half a pound^[5], more than 225 grams, per day!

The majority of all this sugar is hidden in processed foods and beverages, so to address obesity and related health issues like diabetes and heart disease, ridding your diet of processed fare is key for success.

Clinical Scientist Sets the Record Straight on Hazards of Sugar

By Dr. Mercola

Dr. Richard Johnson is the head of nephrology at the University of Colorado and is actively engaged in clinical research. Over the past 25 years,much of his research (which is funded by the National Institutes of Health) has focused on fructose and obesity-related diseases.

Not only has he published some 500 papers in the peer-reviewed literature, he’s also authored books along the way. His latest book, The Fat Switch, is a really intriguing book that shatters many of our age-old myths about diet and weight loss.

His hypothesis is that, rather than being driven by eating too many calories and lack of exercise, obesity is primarily driven by eating too much refined sugar, particularly fructose. According to Dr. Johnson:

“The conventional wisdom is that people are eating too much and exercising too little. Of course, there’s a lot of evidence that supports that… It’s too much energy in, too little out, and the rest is turned into fat.

This is the law of thermodynamics, and there’s some truth to it. The issue is that when people talk about this, they seem to think that it’s the culture that’s driving obesity…

But what we know is that animals in general will regulate their weight very tightly… In order to gain weight significantly, you actually have to block your sensation of fullness, so that you’re hungry more, and you have to block your energy output. You actually block the ability to oxidize fat to burn fat.”

How Leptin Resistance Causes Obesity

In order for you to significantly gain weight, you must first become leptin resistant. Leptin is a hormone that helps you regulate your appetite.When your leptin levels rise, it signals your body that you’re full, so you’ll stop eating.

However, as you become increasingly resistant to the effects of leptin,you end up eating more. Many people who are overweight also have an impairment in their  body’s ability to oxidize fat, which leads to a low-energy state.

The question then is: what drives this basic process? Why do you become leptin resistant in the first place?

Dr. Johnson’s research clearly shows that refined sugar (in particular fructose) is exceptionally effective at causing leptin resistance in animals,and it’s very effective at blocking the burning of fat.

“When you give fructose to animals, they lose their ability to controlt heir appetite, they eat more, and they exercise less. Fructose  looks like it’s playing a direct role in weight gain,” he says.

His research also reveals that fructose has effects independent of this mechanism to induce this metabolic syndrome. Whereas fructose increases weight through the standard mechanism of stimulating more food intake and blocking the burning of fat, even when you control caloric intake, fructose can affect body composition.

This is because when you eat fructose, you actually generate more fat in your liver for the same amount of energy intake, compared to other types of sugar… For example, if you calorically restrict an animal but give it a high-fructose diet or a high-sugar diet, it will still produce fatty liver and will still become insulin resistant.

According to Dr. Johnson,fructose has two effects:

1.    It stimulates weight gain through its effects on your appetite and by blocking the burning of fat

2.    It also changes your body composition to increase body fat even when you are on a caloric restriction

Fruits… Are You Eating Too Much of a Good Thing?

Most overweight  Americans have some degree of insulin and leptin resistance. This also includes people with diabetes, and many individuals with high blood pressure or high cholesterol.

If you fall into this category, it would be prudent for you to restrict your fructose consumption to about 15 to 25 grams of fructose per day from all sources.

Those who are normal weight and relatively healthy may also benefit from reducing their intake of fructose, particularly from foods containing high fructose corn syrup or sugar, as the effects of high sugar  and HFCS intake may have effects  that build up over time.

Naturally, fruits also have fructose but contain many beneficial nutrients and anti-oxidants. For someone who is obese, one has to be careful with eating fruits that have substantial fructose content. Some fruits, such as lemons and limes, have minimal fructose content and are safe.

Other fruits, such as grapefruit, kiwi, and berries, also have relatively low fructose content and high levels of nutrients.  However,fruit juices, dried fruits, and some fruits that are rich in fructose (such as pears, red apples, and plums) should be eaten relatively sparingly. Dr. Johnson explains:

“Most animals will regulate their weight very carefully. They even regulate it in a seasonal way. Towards the fall and before winter, many animals will gain weight, particularly animals that hibernate. They will dramatically increase their fat. A lot of them do so by actually becoming leptin resistanta nd by blocking their ability to oxidize fat.

It’s the same mechanism that we see in people who are getting fat except these animals are doing it purposely in preparation for hibernation. It’s a survival advantage.

Normally, a natural fruit is also a source of fructose. But most natural fruits have relatively small amounts of fructose, like four to eight grams. If you eat a lot of fruit, that could be an issue. But they also often have a lot of things that are very healthy, like antioxidants, flavonols, and so forth.

We’ve actually discovered that many of these compounds in natural fruit can counter some of the effects of the fructose. So when you have a fruit that has a small amount of fructose, oftentimes the good components in the fruit can keep it neutralized.”

Interestingly, as a fruit ripens, the sugar content goes up while many of the antioxidants and other beneficial nutrients go down—and animals appear to instinctively know this. Bears, for example, will eat huge amounts of berries in the fall to fatten up. It’s worth keeping this in mind, as the fructose in fruit can add up quickly if you eat a lot of it.

“There was just a paper published in the British Medical Journal, which looked at individual fruits as a risk factor for obesity and diabetes,” Dr. Johnson says. “Certain fruits, which we know have relatively low-sugar content and very high vitamin and antioxidant contents,are actually quite healthy. Berries, in particular blueberries, are very, very healthy.

But juices, where you put all the fruit together and you get a lot of sugar in one glass, it’s just too much. When you drink that, you can flood your liver with fructose, and then that will overwhelm the benefits of all the antioxidants. You’ll still get an increased risk for fatty liver, obesity, and diabetes from fruit juice.”

Obesity Increases Your Body’s Absorption of Fructose

Another interesting tidbit is that if you’re insulin resistant and obese, it doesn’t take much fructose to activate the processes that will keep you fat. Some of Dr. Johnson’s most recent research shows that the more high-fructose corn syrup you eat, the more you absorb and the more you metabolize it. Thus, eating fruits may be more of an issue if you are insulin resistant, whereas fruit intake is likely safer or even beneficial if you are lean and healthy.

This helps explain the paradox of how some very fit people can eat a lot of fruit without gaining any weight. I’m not insulin resistant, and when I decided to play around with adding some extra fruit to my diet on strength training days, I actually lost five pounds, which to me didn’t make sense at first, since fructose should do the opposite. Part of that may be related to the fact that my body was optimized to burn fat as my primary fuel,as I was regularly practicing intermittent fasting.

According to Dr. Johnson, if you exercise regularly, a small amount of fructose can actually be quite beneficial, because the fructose will accelerate glucose absorption in your gut and improve muscle performance. But it really depends on how your body metabolizes the fructose. Your body normally cannot absorb fructose well. But the more fructose you eat, the more the transporters that allow for fructose uptake in your gut are turned on.Hence, the more fructose your body will absorb. Lean children tend to only absorb about half of the fructose they consume, whereas obese children who have fatty liver disease absorb close to 100 percent.

“Not only that – the kids with fatty liver, we’ve previously shown that they have high levels of enzymes in their liver that metabolize the fructose.Not only did they absorb more, but they metabolized it more effectively. This is a problem,” he says.

The Power of Intermittent Fasting

Intermittent fasting is a powerful tool to help you resolve your insulin and leptin resistance. It’s also one of the fastest ways to shed excess pounds,as it helps shift your body from burning sugar to burning fat as its primary fuel. To me, the most remarkable aspect of intermittent fasting is that once you make the transition, your hunger and cravings for sweets virtually disappears.

Granted, in order to get it right, you need to severely restrict your sugar or fructose intake. A healthy diet becomes all the more important when you start intermittently fasting. Ideally, you’ll want to swap your non-vegetable carbs for healthful fats. Most  benefit from anywhere from 50 to 70 percent of their daily calories in the form of healthful fat, such as avocado, olives, butter, nuts (I prefer macadamia and pecans), and coconut oilfor example.

When it comes to protein, Dr. Johnson agrees that most people could benefit from cutting down on animal protein, especially those high in purines,such as shrimp and lobster. According to Dr. Johnson, a high animal protein diet can accelerate kidney disease, and this appears to be a result of the purines. The following infographic offers a quick review of the basics of intermittent fasting. For a more in-depth review, please see this previous article.

Exercising while fasting can further boost results. A simple way of doing this is to exercise in the morning, and skipping breakfast. As explained by Dr. Johnson:

“If you exercise at night, you’re basically burning primarily your glycogen and carbohydrate stores. You don’t actually burn too much fat. But if you exercise in the morning, you burn more fat than carbohydrates.

The question is why? The reason is that as soon as you quit eating,you’re burning the carbohydrates in your liver. It takes about eight to 10 hours for the glycogen to be completely depleted. What happens is that every time you get a good night’s sleep, during that time your body is burning off the carbohydrates. In the morning, you are basically in a low-carbohydrate state, and you’re now burning fat. That’s why exercising in the morning burns more fat, because you don’t have the big carbohydrate stores.”

If you need to eat a little in order to exercise, make sure to avoid all sugars and carbs. That means no bread products or juices, for example.Essentially, you want to carbohydrate-restrict completely in the morning, in order to allow your body to keep burning fat instead of sugar. As noted by Dr.Johnson, another “trick” to really making intermittent fasting work for you is to restrict most all your non-veggie carbs to a very short period of time each day (typically dinner). He recommends restricting your carb consumption to a window of just two hours per day.

Exercise Stimulates Your Body’s Energy Production

Exercise is really important in this entire process. Not only does it help burn off fat; it also stimulates your mitochondria. Mitochondria are the “power stations” inside your cells that produce the energy that drives your body. As explained by Dr. Johnson, sugar and obesity are both associated with a decrease in the energy levels in your cells, because of the adverse effects sugar has on your mitochondria. Over time, obese people actually lose mitochondria. There are only three factors that stimulate mitochondria really well, according to Dr. Johnson, and those are:

1.    Exercise

2.    Vitamin C (it even helps block some of the adverse effects of sugar. Dr. Johnson recommends getting about 500 mg of vitamin C per day)

3.    Dark, raw chocolate,high in flavonols

Uric Acid as a Marker for Fructose Toxicity

Dr. Johnson promotes using your uric acid level as a marker for fructose toxicity, which we’ve discussed at some length in aprevious interview. Interestingly, for whatever reason, I have a relatively high baseline uric acid level. It’s above Dr. Johnson’s ideal recommendation of 5 or less. Mine’s typically closer to 6.When I implemented intermittent fasting and eliminated most carbs from my diet,replacing them with high quality fats, my uric acid shot up closer to 8. Still,I have no symptoms of gout or other uric acid-related issues. I often wondered if perhaps it was a complication of intermittent fasting, however according to Dr. Johnson, such an effect is fairly normal when you first start fasting and become ketotic.

“We don’t really know why. It might be a compensation mechanism. But it does come down over time under a ketotic diet,” he says.

That said, uric acid is a very strong predictor for developing obesity,diabetes, insulin resistance, and fatty liver. If you have a high-serum uric acid—7 or higher—your risk for developing diabetes, hypertension, obesity, and metabolic syndrome is significant.

Why Many Need General Carb Restriction in Addition to Restricting Fructose

Dr. Johnson recently published a paper in the peer-reviewed journal Nature Communications, showing that restricting fructose may not be enough if you’re severely overweight or obese. General carb restriction may also be needed in such cases. The reason for this is that restricting carbs allows you to burn off glycogens. But Dr. Johnson’s team has also made another significant discovery, which explains why general carb restriction is necessary for those struggling to shed excess pounds:

“We’ve recently had another discovery: carbs like glucose or flour and bread may be able to cause metabolic syndrome in their own right, but it’s through fructose. How does that work?  What we did is we fed animals glucose. That’s a different sugar. There’s no fructose in it. It’s what’s present in flour and bread.  When we fed mice a high-glucose diet,to our amazement, they actually over time started to develop fatty liver,insulin resistance, obesity, and all those bad things.

When we studied them, we found that they were converting some of the glucose to fructose in their liver. Even though they weren’t eating fructose,they were able to use the white flour and the glucose that they eat to convert it to fructose in their body.

We then used special mice that cannot metabolize fructose. They are lean, healthy machines. When we gave them glucose, they did not get fatty liver and they did not get insulin resistance. We could show that the mechanism by which carbs are causing fatty liver is actually still through fructose.”

So, the bottom line is that this is another argument for avoiding bread,rice, and other non-vegetable carbs—especially if you are insulin resistant. If you’re trying to lose weight, restricting carbohydrates will your body to burnfat better, and prevent fructose from being formed in your liver.

The Difference Between High Fructose Corn Syrup and Table Sugar

According to Dr. Johnson, most of the fructose you get comes from table sugar, which is sucrose, and from high-fructose corn syrup. Whole fruits actually play a minimal role in the amount of fructose most people eat Dr.Johnson explains:

“Sucrose is table sugar. It comes from sugar cane and sugar beets. It’s a molecule of glucose and fructose that are bound together in what we call as disaccharide. But basically, the glucose and fructose are bound together. One gram of sucrose is half a gram of fructose.

High-fructose corn syrup is a mixture of fructose and glucose that are mixed freely together. The ratio can vary. Usually, like in soft drinks, the amount of fructose is higher than the amount of glucose. It’s typically 55 percent fructose and 45 percent glucose. A recent study showed that the industry sometimes adds even more fructose in soft drinks; a lot of times it’s 60 percent or 65 percent. It’s really quite a significant amount of more fructose than you see with table sugar.”

There are important differences between these two types of sugars. Dr.Johnson’s team has done studies comparing the metabolic effects of fructose and sucrose, finding that high-fructose corn syrup causes greater increases in fructose blood levels, higher uric acid rise, and a higher rise in blood pressure. The unbound form of fructose also causes more fatty liver disease in animals than the bound form found in sucrose.

“The bottom line is it looks like high-fructose corn syrup is different from sucrose,” he says. “It looks like it is worse.But both of them are major sources of fructose. You don’t really want to switch from high-fructose corn syrup to table sugar; you want to reduce both. But in terms of effects, they are different. I believe high-fructose corn syrup is biologically worse than sugar.”

Understand the Ramifications of a High-Fructose/High-Carb Diet

People everywhere are finally waking up to the indisputable fact that all sugars are not created equal when it comes to the physical end results they create. Again, part of what makes fructose so unhealthy is that it is metabolized by your liver to fat in far more rapidly than any other sugar. But recent research also reveals that, if you are overweight or obese, your liver tends to convert some of the glucose you consume into fructose, even if you’re not eating fructose primarily from sources such as HFCS or sugar.

What this means is that if you are overweight, or insulin and leptin resistant, you likely need to restrict not only fructose from your diet in order to shed the excess weight, but other non-vegetable carbohydrates (such as potatoes, rice, and grains) as well. In addition to that, maintaining a regular eating schedule can be very helpful. Personally, I believe there is good reason to consider a scheduled eating or intermittent fasting program. There is an emerging consensus that narrowing the window of time that you consume food may have enormous health benefits and also help you reduce your percentage of body fat.

I’ve revised my own eating schedule to eliminate breakfast and restrict the time I eat food to a period of about six to seven hours each day, which is typically from noon to 6 or 7 pm for the majority of days. This still gives me a net fasting time of 17-18 hours a day. However,about 25 percent of the time I am traveling, so I’m more liberal on those days.Additionally, when I am at my ideal body weight, I will have fruit immediately before or after a workout. To learn more, please see my previous article, “The Power of Intermittent Fasting.”

WHO calls on countries to reduce sugars intake among adults and children

4 MARCH 2015 ¦ GENEVA – A new WHO guideline recommends adults and children reduce their daily intake of free sugars to less than 10% of their total energy intake. A further reduction to below 5% or roughly 25 grams (6 teaspoons) per day would provide additional health benefits.

• >Guideline on sugars intake for adult and children

Free sugars refer to monosaccharides (such as glucose, fructose) and disaccharides (such as sucrose or table sugar) added to foods and drinks by the manufacturer, cook or consumer, and sugars naturally present in honey, syrups, fruit juices and fruit juice concentrates.

“We have solid evidence that keeping intake of free sugars to less than 10% of total energy intake reduces the risk of overweight, obesity and tooth decay,” says Dr Francesco Branca, Director of WHO’s Department of Nutrition for Health and Development. “Making policy changes to support this will be key if countries are to live up to their commitments to reduce the burden of noncommunicable diseases.”

The WHO guideline does not refer to the sugars in fresh fruits and vegetables, and sugars naturally present in milk, because there is no reported evidence of adverse effects of consuming these sugars.

Much of the sugars consumed today are “hidden” in processed foods that are not usually seen as sweets. For example, 1 tablespoon of ketchup contains around 4 grams (around 1 teaspoon) of free sugars. A single can of sugar-sweetened soda contains up to 40 grams (around 10 teaspoons) of free sugars.

Worldwide intake of free sugars varies by age, setting and country. In Europe, intake in adults ranges from about 7-8% of total energy intake in countries like Hungary and Norway, to 16-17% in countries like Spain and the United Kingdom. Intake is much higher among children, ranging from about 12% in countries like Denmark, Slovenia and Sweden, to nearly 25% in Portugal. There are also rural/urban differences. In rural communities in South Africa intake is 7.5%, while in the urban population it is 10.3%.

Reducing sugars intake to less than 10% of total energy: a strong recommendation

The recommendations are based on analysis of the latest scientific evidence. This evidence shows, first, that adults who consume less sugars have lower body weight and, second, that increasing the amount of sugars in the diet is associated with a weight increase. In addition, research shows that children with the highest intakes of sugar-sweetened drinks are more likely to be overweight or obese than children with a low intake of sugar-sweetened drinks.

The recommendation is further supported by evidence showing higher rates of dental caries (commonly referred to as tooth decay) when the intake of free sugars is above 10% of total energy intake compared with an intake of free sugars below 10% of total energy intake.

Based on the quality of supporting evidence, these recommendations are ranked by WHO as “strong”. This means they can be adopted as policy in most situations.

Further reduction to less than 5% of total energy intake: a conditional recommendation

Given the nature of existing studies, the recommendation of reducing intake of free sugars to below 5% of total energy is presented as “conditional” in the WHO system for issuing evidence-based guidance.

Few epidemiological studies have been undertaken in populations with a low sugars intake. Only three national population-wide studies allow a comparison of dental caries with sugars intakes of less than 5% of total energy intake versus more than 5% but less than 10% of total energy intake.

These population-based ecological studies were conducted during a period when sugars availability dropped dramatically from 15kg per person per year before the Second World War to a low of 0.2kg per person per year in 1946. This “natural experiment”, which demonstrated a reduction in dental caries, provides the basis for the recommendation that reducing the intake of free sugars below 5% of total energy intake would provide additional health benefits in the form of reduced dental caries.

WHO issues conditional recommendations even when the quality of evidence may not be strong on issues of public health importance. A conditional recommendation is one where the desirable effects of adhering to the recommendation probably outweigh the undesirable effects but these trade-offs need to be clarified; therefore, stakeholder dialogue and consultations are needed before the recommendation is implemented as policy.

Updating the guideline on free sugars intake is part of WHO’s ongoing efforts to update existing dietary goals to prevent NCDs. The sugars guidelines should be used in conjunction with other nutrient guidelines and dietary goals, in particular those related to fats and fatty acids, including saturated fat and trans-fat.

In March 2014, WHO opened a public consultation on the then draft sugars guideline to seek inputs from all stakeholders. More than 170 comments were received from representatives of government agencies, United Nations agencies, nongovernmental organizations, industries and academic institutions as well as other interested individuals. An expert peer review process was also undertaken in 2014. The final guideline was prepared taking into account comments received from the public consultation and expert peer review.

Countries can translate the recommendations into food-based dietary guidelines that consider locally available food and customs. Additionally, some countries are implementing other public health interventions to reduce free sugars intake. These include nutrition labelling of food products, restricting marketing to children of food and non-alcoholic drinks that are high in free sugars, fiscal policies targeting foods and beverages high in free sugars, and dialogue with food manufacturers to reduce free sugars in processed foods.

Note to editors

Reducing free sugars intake to less than 10% of total daily energy intake was recommended by the WHO Study Group for the first time in 1989 and was further elaborated by a joint WHO/FAO Expert Consultation in 2002. This new updated WHO guideline calls for further reduction of free sugars intake to less than 5% of total energy intake if possible.

Promoting healthy diet was a key theme of the Second International Conference on Nutrition (ICN2) convened jointly by the Food and Agriculture Organization of the United Nations (FAO) and WHO in November 2014. At ICN2, more than 170 countries adopted the Rome Declaration on Nutrition, and a Framework for Action, which highlight the need for global action to end all forms of malnutrition, including obesity and diet-related NCDs.

The sugars guideline is also part of WHO’s effort to reach targets set by the Global Action Plan for NCDs 2013-2020 to halt the rise in diabetes and obesity and reduce the burden of premature deaths due to NCDs by 25% by 2025. Similarly, the sugars guideline contributes to the work of WHO’s Commission on Ending Childhood Obesity, which aims to raise awareness and build momentum for action to address childhood obesity.

• Global action plan for the prevention and control of NCDs 2013-2020

For more information, contact:

Christian Lindmeier
Telephone: +41 22 791 1948
Mobile: +41 79 5006552
E-mail: lindmeierch@who.int

Olivia Lawe Davies
Telephone: +41 22 791 1209
Mobile: +41 79 475 55 45
E-mail: lawedavieso@who.int