Amy Goss
Author: Amy Goss, PhD, RD (“Diet Quality and Health Aging: the Effects of Macronutrient Manipulation on Metabolic Health and Physical Function in Older Adults with Obesity”):
Aging is associated with an elevated risk of metabolic diseases such as type 2 diabetes, cardiovascular disease, and sarcopenia (loss of muscle tissue). Obesity in older adults may further increase these risks as well as adversely affect a patient’s quality of life and/or ability to perform normal daily activities.
In particular, the accumulation of intra-abdominal adipose tissue (IAAT), intermuscular adipose tissue (IMAT), and lipid accumulation in other ectopic depots may actually be the most relevant fat depots in determining cardio-metabolic risk in older adults. IAAT and IMAT are linked to insulin resistance and may greatly contribute to a pro-inflammatory state. Together, insulin resistance and inflammation can inhibit skeletal muscle synthesis and contribute to poor metabolic and functional outcomes in obese, aging adults.
Typically, obese individuals are advised to improve their overall health by restricting their caloric intake in order to lose weight. However, for aging adults, significant weight loss through these means often results in the loss of lean mass and/or bone, which can be profoundly detrimental to their physical function.
Goss and other nutritional obesity researchers at UAB have determined that a change in diet quality may be a more appropriate approach to the treatment of aging, obese adults, because it can prevent the loss of lean tissues, reduce body fat, and improve their metabolic health.
Their previous research has shown that, among overweight/obese adult patients placed on an eight-week eucaloric (consuming roughly the same number of calories they burned each day) diet that was reduced in consistent carbohydrates (CHO) and higher in fat—resulted in preferential loss of IAAT (-15%) when compared to a standard, low-fat diet.
In a similar study among women with polycystic ovary syndrome (PCOS), the consumption of a eucaloric diet low in CHO and higher in fat (relative to a standard, low-fat diet) resulted in preferential loss of total fat (-5%), IAAT (-9%), and IMAT (-11%), maintenance of lean body mass, and improvements in insulin sensitivity and the lipid profile. These findings suggest that a diet that is low in CHO and rich in complete, high-quality proteins and essential fatty acids may promote preferential loss of adipose tissue from metabolically harmful depots without compromising lean mass.
Preliminary data from a randomized clinical trial in adults over the age of 60 with obesity suggest that a carbohydrate-restricted (versus a fat-restricted) diet can result in significantly improved metabolic health and muscle strength. After eight weeks of consuming the diet, participants in the carbohydrate-restricted diet group experienced preferential loss of body fat mass, preserved lean body mass, and saw significant improvements in insulin sensitivity, indicating a reduced risk of type 2 diabetes and improvements in muscle strength.
Dr. Goss concluded by stating that UAB’s ongoing nutritional study has shown promising results that suggest improvements in diet quality, i.e. avoiding highly processed carbohydrate-containing foods (such as grains and sugar), may be a simple, non-pharmacological way to prevent and/or reverse sarcopenia and age-related declines in metabolic health among adults with obesity. This could ultimately lead to improvements in patients’ overall health, physical function, and quality of life.
Contact Jessica Alvarez, PhD, RD with questions.
About this Lecture
On Thursday, May 12, 2016, the Emory Center for Clinical and Molecular Nutrition hosted guest speaker Amy Goss, PhD, RD, a postdoctoral fellow at the Nutrition Obesity Research Center at the University of Alabama at Birmingham (UAB) at its monthly nutritional seminar. Dr. Goss presented “Diet Quality and Health Aging: the Effects of Macronutrient Manipulation on Metabolic Health and Physical Function in Older Adults with Obesity” at the Emory University School of Medicine.
Related Links
- Emory University Department of Medicine
- Health and Exposome Research Center: Understanding Lifetime Exposures (HERCULES)
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