An important study on sugar, calories and obese children’s health
This is one of the most important studies on sugar, calories and children’s health to date. It was conducted by researchers at UC San Francisco and Touro University California. The key points are:
The study indicates that calories are not created equal; sugar and fructose are particularly dangerous.
Reducing consumption of added sugar, even without reducing calories or losing weight, has the power to reverse a cluster of chronic metabolic diseases, including high cholesterol and blood pressure, in children in as little as 10 days.
“This study definitively shows that sugar is metabolically harmful not because of its calories or its effects on weight; rather sugar contributes to metabolic syndrome. This is the strongest evidence to date that the negative effects of sugar are not because of calories or obesity.”
Jean-Marc Schwarz, PhD at Touro University California who also appears in the film said: “I have never seen results as striking or significant in our human studies; after only nine days of fructose restriction, the results are dramatic and consistent from subject to subject. These findings support the idea that it is essential for parents to evaluate sugar intake and to be mindful of the health effects of what their children are consuming.”
After just 9 days on the sugar-restricted diet, virtually every aspect of the participants’
metabolic health improved, without change in weight.
“All of the surrogate measures of metabolic health got better, just by substituting starch for sugar in their processed food — all without changing calories or weight or exercise,” said Lustig. “This study demonstrates that ‘a calorie is not a calorie.’ Where those calories come from determines where in the body they go. Sugar calories are the worst, because they turn to fat in the liver, driving insulin resistance, and driving risk for diabetes, heart, and liver disease. This has enormous implications for the food industry, chronic disease, and health care costs.”
Here is the study: http://onlinelibrary.wiley.com/doi/10.1002/oby.21371/abstract
Here is a great Question and Answer session on the study for those wanting to know more:
Q. Who did this study?
A. Researchers at UCSF and Touro University performed this study in a team fashion. It
took 5 years to complete. The study team consisted of Robert Lustig and Jean-Marc
Schwarz (Principal Investigators), as well as Susan Noworolski, Kathleen Mulligan, and
Alejandro Gugliucci (Co-Investigators). We also had many ancillary support staff that
assisted with the protocol.
Q. Why did we do this study?
A. We knew that excessive added sugar consumption is associated with the development of
the various diseases of metabolic syndrome, including cardiovascular disease, type 2
diabetes, hypertension, and lipid problems. However, some studies suggested that the
detrimental effects of dietary sugar were due to extremely high dosing, excess calories, or
because of effects on weight gain. If so, then sugar would not be different from any other
foodstuff that provides calories. In order to answer this question, we had to dissociate the
metabolic effects of dietary sugar from its calories and its effects on weight gain. In order to
clarify, we focused on the metabolic impact of certain calories, rather the quantity of
calories in the overall diet.
Q. How did we do this study?
A. We did not want to give sugar to people to see if they got sick; that has already been
done (1-3), and critics would raise concerns about excessive dosing and excessive calories
(4). Instead, we wanted to take sugar away from people who were already sick to see if
they got well. But if they lost weight, critics would argue that the drop in calories or the
weight loss was the reason for the clinical improvement. Therefore, the study was
“isocaloric,” which means that we had to give back the same number of calories in starch as
we took away in sugar, and we had to make sure that they did not lose weight.
Q. Who participated in the study?
A. A total of 43 children participated, ages 8-19, from the Weight Assessment for Teen and
Child Health (WATCH) Clinic at UCSF, and from surrounding clinics. Of these, 27 were
Latino, and 16 were African-American. Each person was obese, and had at least one other
co-morbidity that demonstrated that they had metabolic problems. All were high
consumers of added sugar in their diets (e.g. soft drinks, juices, pastries, breakfast cereals,
salad dressings, etc.).
Q. What did we do in this study?
A. We assessed their home diets by two questionnaires to determine how many calories,
and how much fat, protein, and carbohydrate they were eating. We had them come to the
hospital for testing on their home diet. Then, for the next 9 days, we catered their meals.
The macronutrient percentages of fat, protein, and carbohydrate were not changed. We fed
them the same calories and percent of each macronutrient as their home diet; but within
the carbohydrate fraction, we took the added sugar out, and substituted starch. For
example, we took pastries out, we put bagels in; we took yogurt out, we put baked potato
chips in; we took chicken teriyaki out, we put turkey hot dogs in — although we still gave
them whole fruit. We reduced their dietary sugar consumption from 28% to 10% of
calories, in accordance with the World Health Organization’s recommendation for free or
added sugars. We gave them extra snacks. We gave them a scale to take home, and each day
they would weigh themselves. If they were losing weight, we told them to eat more. The
goal was to remain weight-stable over the 10 days of study. On the final day, they came
back to the hospital for testing on their experimental low-added sugar diet. The study team
analyzed the pre- and post-data in a blinded fashion so as not to introduce bias.
Q. How did the children do on the study diet?
A. Of the 43 children, 42 described the study diet as highly palatable. Despite our best
efforts to stabilize these children’s weights for the 10 days, they lost an average of 0.9 kg or
2 pounds. Most of the children told us that they couldn’t eat more; they were too full.
Because of the small weight loss, we adjusted all results statistically to control for the
weight loss. We performed body composition analysis, which told us that the weight loss
was in the fat-free mass compartment (either muscle or water), rather than in the fat
compartment; so the weight loss was not body fat.
Q. What were the results of this study?
A. We looked at three types of data. 1) Diastolic blood pressure decreased by 5 points.
2) Baseline blood levels of analytes associated with metabolic disease, such as lipids, liver
function tests, and lactate (a measure of metabolic performance) all improved significantly.
3) Fasting glucose decreased by 5 points. Glucose tolerance improved markedly. Fasting
insulin levels fell by 50%. Every one of these changes was highly significant. In sum,
virtually all aspects of their metabolic health improved. These indicate that these children
improved their metabolic status in just 10 days, even while eating processed food, by just
removing the added sugar and substituting starch. The metabolic improvement was
unrelated to their caloric intake, and unrelated to changes in weight or body fat.
Q. What are the limitations of the study?
A. 1) We did not do an external control group; this would have been nearly impossible to
do, because their calorie counts are underestimated, and you would not be able keep them
from knowing what they ate, unless you tube-fed them, which is unlawful. 2) The children
did lose an average of 2 pounds, although based on the pattern of weight loss and the body
composition analysis, we believe this was water and not fat, and water loss should not lead
to metabolic improvement. Of the 43 children, 10 did not lose weight. We analyzed them
separately (called sensitivity analysis) and showed that their metabolic health improved as
well. Thus, the metabolic improvement is not due to weight loss or caloric deficit.
Q. What does this study show?
A. 1) This study conclusively proves that all calories are not the same (“a calorie is not a
calorie”); because substituting starch for sugar improved these children’s metabolic health
unrelated to calories or weight gain. 2) This study shows that we can improve the
metabolic health of obese children in just 10 days by removing the added sugar from their
diet. 3) This study demonstrates that added sugar contributes to metabolic syndrome in
children. This study does not prove that sugar is the sole, or even primary cause of
metabolic syndrome; but it is clearly a modifiable cause. Based on the results of this and
other studies, a compelling case is made for appropriate public education and rational
policy change to improve the lives and health of children (and adults) worldwide.
Q. What implications can we derive from this study?
A. When it comes to chronic disease, the quality of our food is as important, and possibly
even more important, than the quantity of food consumed. Restriction of added sugar
should be a first step in the prevention or treatment of chronic disease in children.
Although we did not study adults, other studies demonstrate similar improvements when
sugar is restricted. Sugar is added to processed food for palatability, convenience, cost, and
shelf life. Of the 600,000 items in the American food supply, 74% have been adulterated by
added sugar (5). Processed food is directly implicated in the rise of the various aspects of
metabolic syndrome unrelated to calories. The food industry has said that we only have
correlation, not causation, for sugar and chronic disease. However, these data, when taken
with other studies, provide causation. This study bolsters the evidence that the food
industry argument of added sugar being no more harmful than other components of
processed food is fallacious. It is now clearer than ever that recommended limits on added
sugar, provided by leading health organizations (WHO, AHA, USDA/DGAC, etc.) should be
taken seriously. Additionally, added sugar should be included on all food labels, so that
consumers can make informed decisions about their children’s health.