5 questions with Stuart Phillips, Ph.D. about protein needs and exercise science research

Stuart Phillips, Ph.D. is a Professor and Tier 1 Canada Research Chair in the Department of Kinesiology at McMaster University in Hamilton, Ontario.

Stu Phillips PhD McMaster U
Stuart Phillips, Ph.D.

Interviewer Mike Roberts, Ph.D.: Stu, before interviewing you I’d be remiss if I didn’t say that you’re my hero.  For some folks it’s LeBron James or Tom Brady.  For me, it’s you because of your excellent contributions to science.  Anyhow, let’s get into it.

Stuart Phillips, Ph.D. [SP]: Ha, you are too kind… those are generous words, thank you!

Q1: For young, college-aged weight lifters, how much protein should she/he be consuming per day?
[SP]: I think they should aim for between 1.6 and 2.2 g protein/kg body weight/day (0.7-1 g protein/lb body weight/day) and try and divide that into 3, maybe 4, meals per day and evenly distribute that protein, if possible. So try and eat protein at every meal. You can certainly eat more protein but the gains you make if you’re lifting won’t be any greater. Some folks want to say that you lose more fat with intakes beyond this, but there’s no evidence for that concept either.
Q2: Muscle mass loss with aging is a slow process, but is dire in that leads to frailty-related issues.  So, for older folks that are looking to maintain muscle mass how much protein should they consume per day?
[SP]: Good question, and we’re less sure about what older folks require, but I would say their intakes should be at least 1.2 g protein/kg/day and likely up to the same level as younger folks. The main problem in aging is that muscle becomes ‘resistant’ to protein and so older people need to remain physically active, which helps them retain muscle and strength!
Q3: Most of us have always heard that higher-protein diets are bad for the kidneys.  Your laboratory recently published a nice paper challenging this paradigm.  Can you give us the overall theme of that paper?
[SP]: You can credit a urologist/nephrologist, Dr. Barry Brenner, with the hypothesis that higher protein-containing diets would lead to declines in kidney function. That theory is about 40-45 years old and since it there have been no convincing data showing that it’s true. Our paper basically found no evidence for the concept, and in-line with our paper another recent review concluded the same. Thus, there is no evidence to suggest that dietary protein is linked to and/or causative in declines in kidney function or kidney disease.
Q4: In terms of protein supplement recommendations, I’ve personally told folks “not necessary, but practical” in terms of not having to tote around Tupperware with chicken or tuna 24/7.  What are your thoughts on protein supplements?
[SP]: You and I think alike. Supplements are convenient and that’s their biggest appeal. They can provide an isolated source of the nutrient, for example protein, but food trumps a supplement in my view. People, for example, who get their protein from foods have a greater nutrient density in their diet (See our paper on how protein foods contribute to nutrient intake, diet quality, and nutrient adequacy).
Q5: You have always been on the razor’s edge of research.  Are there any new or cutting-edge research initiatives that your laboratory is working on?
[SP]: We’re moving more and more into aging and trying to understand what factors result in pathways to aging ‘well’. We plan on trying to use multi-level omic technologies – genes and proteins – to see if we can determine why some people age well and others do not. We’re certain the aging trajectory is modifiable with exercise as the biggest stimulus and diet a close second, but we’re unsure as to what and how much. Being able to handle big data will be critical for this process, we think!
Thanks so much for the time today, Dr. Phillips.  Look forward to catching up soon.
[SP]: Likewise! Thank you for taking the time!
For more information on Dr. Phillips and his research, check him out on social media:
Twitter: @mackinprof
Instagram: @mackinprof
Facebook: /SMPPh.D
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