Carbohydrates
Episodes
In this clip, Ronald Krauss discusses the negative combinative effect of consuming added sugars and saturated fat together.
In this clip, Dr. Peter Attia explains the complex relationship that exists between cancer cells, the immune system, and IGF-1.
Dr. Eric Verdin explains the importance of the insulin signaling pathway in aging and highlights both animal and human research in this area.
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In this clip, Ronald Krauss discusses the negative combinative effect of consuming added sugars and saturated fat together.
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In this clip, Dr. Peter Attia explains the complex relationship that exists between cancer cells, the immune system, and IGF-1.
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Dr. Eric Verdin explains the importance of the insulin signaling pathway in aging and highlights both animal and human research in this area.
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Dr. Matthew Walker describes how sleep deprivation drives a preferential desire for high carbohydrate foods.
Topic Pages
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Sugar-sweetened beverages (SSBs)
Sugar-sweetened beverages such as soda, juice, and sports drinks provide large doses of rapidly absorbable sugar, posing a unique risk to health.
News & Publications
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When healthy, lean individuals ate a Western-style diet for one week, their hippocampal-dependent learning and memory and appetite control declined. royalsocietypublishing.org
The Western Style Diet, sometimes referred to as Standard American Diet (SAD), is a dietary pattern characterized by high intake of refined carbohydrates, fatty meats, added fats, and sodium, and low intake of whole grains, fruits, and vegetables. The Western dietary pattern has been implicated in the pathogenesis of many chronic diseases and conditions, including overweight and obesity, type 2 diabetes, high blood pressure, and heart disease. Findings from a recent study suggest that the Western dietary pattern impairs hippocampus-dependent learning and memory and drives loss of appetite control.
The hippocampus is a small organ located within the brain’s medial temporal lobe. It is associated primarily with memory (in particular, the consolidation of short-term memories to long-term memories), learning, and spatial navigation. Data from rodent studies suggest that adherence to a Western dietary pattern impairs hippocampal-dependent learning and memory (HDLM). The hippocampus also plays a role in food intake by regulating appetite. Altered hippocampal function subsequent to exposure to a Western-style diet may create a vicious cycle state that promotes increased consumption of unhealthy foods that, in turn, drives further hippocampal dysfunction.
The study involved 110 lean, healthy Australian adults between the ages of 17 and 35 years who adhered to a healthy, non-restrictive dietary pattern. The authors of the study randomized the participants to either a one-week Western-style diet intervention group or a habitual-diet control group.
On the first and eighth days of the study, the participants in the Western diet group ate a breakfast that included a toasted sandwich and a milkshake (high in saturated fat and added sugar). On the second through seventh days of the study, the participants ate two Belgian waffles for either breakfast or dessert for four of the study days. On the other two study days, they obtained their main meal and a drink or dessert from a set of options from a popular fast-food chain. They followed their normal dietary pattern for all other meals. The participants in the control group ate a breakfast consisting of a toasted sandwich and a milkshake (low in saturated fat and added sugar) on the first and eighth days and followed their normal diet for all other meals.
The authors of the study assessed the participants' HDLM function as well as their appetite control before and after the intervention and control periods and again at a three-week follow-up assessment. They found that among those who followed the Western-style diet, HDLM performance declined, compared to the control group. Their appetite control declined as well, and this was strongly correlated with HDLM decline.
These findings suggest that even short-term consumption of a Western-style diet may impair learning and appetite control due to impaired hippocampal function. This lack of appetite control could promote overeating and drive weight gain.
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Alterations in gut microbial fermentation modulate the efficacy of exercise for diabetes prevention and management. www.cell.com
Public health officials and healthcare providers commonly recommend exercise as a strategy to prevent or manage the symptoms of type 2 diabetes, but the cardiometabolic response to exercise is variable. Whereas exercise improves insulin sensitivity and promotes cardiovascular health in most adults (responders), exercise exerts a paradoxical effect in which metabolic health is compromised in as many as 69 percent of adults (non-responders). Findings from a recent study suggest the variable effects of exercise in people with prediabetes may be due to alterations in gut microbial fermentation.
Microbial fermentation is the process by which gut bacteria break down and utilize carbohydrates in the gut. The metabolites produced during microbial fermentation include short-chain fatty acids and branched-chain amino acids, which are absorbed and used by the host. Short-chain fatty acids improve symptoms of diabetes, but branched-chain amino acids have the converse effect
The study involved both humans and mice. The human study included 39 overweight or obese men with prediabetes who were between the ages of 20 and 60 years. Participants were randomized to engage in either sedentary activities or supervised exercise training for 12 weeks. They maintained their usual diet throughout the study period. At the end of the 12-week period, fecal microbial samples from two of the participants (responders and non-responders) were transplanted into obese mice.
The results demonstrated that the responders' microbiota displayed increased production of short-chain fatty acids, whereas those of the non-responders displayed increased production of brain-chain amino acids. Fecal microbial transplantation from responders mimicked the effects of exercise on alleviation of insulin resistance in the mice, but fecal transplants from the non-responders did not. These findings may augment and facilitate clinical management of symptoms of diabetes.
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Eating a low-fat diet may reduce testosterone levels in men. www.eurekalert.org
As many as half of all men living in the United States have low testosterone levels, a condition characterized by libido loss and erectile dysfunction. Lifestyle modifications such as exercise and diet (to promote weight loss) are often recommended as a means to restore testosterone levels. Findings from a new study suggest that eating a lower-fat diet may contribute to low testosterone levels.
The study drew on data from 3,100 men between the ages of 18 and 80 years who were enrolled in NHANES studies between 1998 and 2012. The participants completed 2-day diet records and provided blood samples for testosterone analysis. The men’s diets were classified as low fat, low carbohydrate, Mediterranean, or non-restrictive.
Men who ate a low fat or Mediterranean diet had lower testosterone levels on average than men who ate a non-restrictive diet. These findings suggest that low-fat dietary recommendations for men who have low testosterone may have unintended consequences that should be weighed against any possible benefits associated with weight loss.