Are You Predisposed To Obesity?
It’s not news that obesity rates are astronomical. Yet the increased availability of high fat and high-sugar foods only partly explains the high incidence of obesity around the world. For one thing, while we are all given the same amount of available food, only some people are obese, while others remain at healthy weights.
So just why do some people struggle with obesity while others seem unaffected?
This is a question that has also been pondered by addiction expert Francesco Leri, Associate Professor of Neuroscience and Applied Cognitive Science at the University of Guelph.
The difference, Leri suggests, is that we are all not equally vulnerable to addiction. As surveys of cocaine consumption have shown, many individuals try these drugs, yet only a small percentage of them become addicted. Many others, including Leri, have asserted that certain foods – especially those that are artificially enhanced with sweeteners – can act on our brains much in the same way drugs like cocaine do, with some people being more vulnerable to addiction than others.
To test this theory, Dr. Leri investigated the behavioral, chemical and neurobiological changes induced by consumption of “addictive foods” (those containing unnaturally high concentrations of sugar, fats, and taste enhancers – such as Oreo cookies and Fruit Loops cereal) in the bodies and brains of rats.
According to Leri, the results provided, “convincing neurobiological and behavioral evidence indicating that addiction to food is possible” (Leri, 2013).
Yet the question we might be asking – and the next part of Leri’s research – is: Are some people more susceptible to food addiction than others? The answer appears to have something to do with at what age we consume them. Food addictions, it seems, appear to be tied to critical periods in youth.
Recruiting 25 mothers and infants, researchers at the Keck School of Medicine of USC examined the babies at 1 month old and again when they were 6 months old. The infants were fed breast milk, consumed less than 8 ounces of formula a week and had no solid foods, according to their mothers. The mothers were instructed to fast for three hours before the visit. At each examination, researchers took a breast milk sample from each mom and scanned it for sugars such as lactose, glucose, and fructose. They also measured each baby’s fat mass, muscle mass, and bone mass.
Adjusting their results for the sex of the infant and the weight at 1 month, the researchers found that just 10 milligrams (about a grain of rice) of fructose from breast milk a day, caused adverse changes in the baby’s body composition during growth. Clarifying the results, Michael Goran, the lead author of the study and founding director of the Childhood Obesity Research Center at the Keck School of Medicine, explained, “A single microgram of fructose per milliliter of breast milk – that’s 1,000 times lower than the amount of lactose found in breast milk – is associated with a 5 to 10 percent increase in body weight and body fat for infants at six months of age,” (Goran, et. al., 2017).
Being found in large quantities in processed foods and soda, such as Frappuccinos, energy drinks, and juice cocktails, fructose is not a natural component of breast milk, Goran noted, and exposing infants and children to higher amounts of sugar during growth and development can produce problems with cognitive development and learning as well as create lifelong risk for obesity, diabetes, fatty liver disease and heart disease (Goran, 2017).
As other studies have demonstrated that fructose and artificial sweeteners are particularly damaging during critical periods of growth and development in children (Goran, 2017), this study, according to Tanya Alderete, co-author of the study and a postdoctoral research scholar at the Keck School of Medicine, shows how ingestion of fructose predisposes a child for obesity – effectively coaching pre-fat storage cells to become fat cells, raising the baby’s risk of one day becoming overweight or obese (Alderete, 2017).
Another study found yet another “critical window”, this time in adolescence.
While earlier findings showed that mothers who eat junk food while pregnant are programming their babies to be addicted to a high fat, high sugar diet by the time they are weaned, and this effect is amplified when mothers eat junk food later in their pregnancy, researchers from the FOODplus Research Center found that these same children then face another developmental challenge in adolescence.
Because their reward system has become desensitized – due to an overexposure to high-fat and high-sugar foods in utero – when these children hit adolescence, a time when the brain and its reward centers grow the fastest, they need more sugar and more fat to get the same “good feeling” as teens with an unaltered opioid and dopamine signaling pathway (Mühlhäusler, et al., 2015).
So if junk food – in particular, high-sugar food – desensitizes the normal reward system, making us crave it more, one question you might be asking yourself is: What about artificial sweeteners?
Despite their approval as food additives following the submission of detailed safety data to the United States Food and Drug Administration (FDA), concerns about their safety and especially about their long-term health effects of artificial sweeteners, such as sucralose and acesulfame-potassium remain. As of late, artificial sweeteners, also including saccharin and aspartame, have received a lot of attention lately because it has been found that they are not inert chemicals with a sweet taste, but active substances that can affect the metabolism. Further, due to concerns about high sugar consumption, and market demand for palatable, low calorie foods, artificial sweeteners become increasingly available in a wide variety of foods.
Given this, researchers enrolled 22 adults aged 18-45 and 11 children aged 6-12 with no known medical conditions and who were not using any medications in a randomized same-subject crossover study. Artificial sweetener concentrations were first measured among adults following ingestion of various doses of sucralose with or without acesulfame-potassium, both in diet soda and mixed in seltzer or plain water, then compared to the results obtained in children.
For any parent the results should be alarming: compared to adults, children had double the concentrations of plasma sucralose after ingestion of a single twelve ounce can diet soda. And if artificial sweeteners are given to infants, the authors speculate the infants’ blood levels may be proportionately even higher as infants have less ability to clear substances from their blood stream (Sylvetsky, et. al., 2016).
These results become even more relevant given that early life exposure to artificial sweeteners may influence a child’s future taste preferences, diet, and metabolic fate. Artificial sweeteners, it seems, provide an intense sweetness that becomes impossible to replicate naturally. Like adolescents with an altered reward system, children who consume high amounts of artificial sweeteners may find themselves reaching for more high-sugar and high-fat foods in search of the same artificial kick that comes with altered sweeteners.
What all of this amounts to is that high-fat, high sugar foods and artificial sweeteners can act on our brains much in the same way addictive substances do – affecting us at critical periods, desensitizing the reward system and causing us to crave them more – effectively hooking us in and predisposing us to a lifelong battle with obesity. Yet what this also explains is just why some people have such a hard time with weight loss. In the next post, we will explore what we can do about it.
Leri, F. (2013). “Addiction to unhealthy foods could help explain the global obesity epidemic, research suggests.” ScienceDaily, 22 May 2013.
Goran, M., Martin, A., Alderete, T., Fujiwara, H., Fields, D. (2017). Fructose in Breast Milk Is Positively Associated with Infant Body Composition at 6 Months of Age. Nutrients, 2017; 9 (2): 146
Mühlhäusler, B. et. al., (2015). “Critical windows to turn away junk food craving.” ScienceDaily, 2 April 2015.
Sylvetsky, A., Bauman, V., Blau, J., Garraffo, M., Walter, P., Rother, K. (2016). Plasma concentrations of sucralose in children and adults. Toxicological & Environmental Chemistry, 2016
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Dorotik-Nana, C. (2017). Are You Predisposed To Obesity?. Psych Central. Retrieved on September 24, 2017, from https://blogs.psychcentral.com/leveraging-adversity/2017/06/are-you-predisposed-to-obesity/