Small Dog Metabolism and Other Unique Characteristics

Rondo P. Middleton, PhD
Nestlé Research Center St. Louis



  • Although small dogs are the same species and subspecies as large dogs, it is now clear that they have very notable metabolic differences.
  • In comparison to larger-breed dogs, smaller dogs have higher energy demands, higher percentage of lean body mass, and a lower level of total antioxidants, increased ability to digest protein, differences in gut microflora, and differences in kidney biology.



Rondo P. Middleton, PhD- Nestlé Research Center St. Louis

Dr. Rondo Middleton completed a doctorate degree in biochemistry in 1999 at the University of California, Riverside, where he studied 1,25 (OH)2 vitamin D3’s ability to regulate gene expression at the transcriptional, translational and post-translational levels. He was hired by Nestlé Purina’s predecessor, Ralston Purina, as a research scientist in 1998. Currently a senior research scientist, Dr. Middleton leads the Healthy Aging Platform at the Nestlé Research Center in St. Louis (pet care basic research). His research interests include metabolism, osteoarthritis, cancer, and aging, among others. Most of his work focuses on molecular aspects, such as gene expression, metabolomics, and systems biology, that support health and wellness.

“Progress in the areas of growth, longevity, metabolic rate as well as the genetic basis of small dogs has made immense strides in the past 10 to 15 years. We are now at a stage where we have begun to understand metabolic differences inherent to small dogs”