Many of you likely know that I love Rogue One type content. Where one line said in passing morphs into a much longer piece of content.
Down the rabbit hole we go…
You may have seen the two paragraphs below on Deconstruct Nutrition and this week’s conversation with Dr. Grant Tinsley and HERE is a deep dive into nuances of body composition metrics. He crushes it and I felt this content is so important I elected just to give this conversation away on the podcast.
“It is important to note that given the likely glycogen loss and accompanying fluid loss that comes from a significant energy deficit and early phase weight loss [1, 2], the potential edema of starting a resistance-training program , and the potential for day-to-day variance in lean body mass measurements via different body composition metrics [4-6] there is a considerable amount of noise in muscle data from the studies above, especially those that utilized untrained participants.”
From How Do We Actually Lose Body Fat?
“In practice, what this means is that if someone is pushing a caloric deficit in order to shed body fat while simultaneously starting or increasing their resistance training schematic I think we can expect to see a lot of chaos on the scale in the first few weeks and in most scenarios it is probably not really worth measuring any body composition metrics for at least 8 weeks and even then we likely can’t pick up significant changes in LBM because the error rates in LBM of the measurements are generally higher than the amount of muscle untrained individuals can gain in those timeframes [4, 7-11] (someone may be able to convince me that in certain scenarios skinfold or ultrasound measurements of subcutaneous fat every two to three weeks could be helpful.)”
From Is Weight Loss Without Exercise Unethical?
My main takeaways from this conversation:
· Rigorous standardization is fundamental to attaining useful body composition data.
· If someone is not consistent with their diet, fluid intake, and training they will very likely lack the ability to collect precise body composition data.
· The ability of these technologies to detect significant/real changes on the individual level will get more and more difficult as the degree of change becomes less and less. In most scenarios, dramatic weight loss and recomposition will very likely surpass both the technological and biological error, whereas it will likely be hard to say if someone gained 1 kg of FFM and lost 1kg of FM is significant.
· You can be more certain you are moving in the intended direction if multiple lines of data are showing similar trends.
Other references we mention in the podcast [12-14].
1. Heymsfield, S.B., et al., Voluntary weight loss: systematic review of early phase body composition changes. Obes Rev, 2011. 12(5): p. e348-61.
2. Muller, M.J. and A. Bosy-Westphal, Effect of Over- and Underfeeding on Body Composition and Related Metabolic Functions in Humans. Curr Diab Rep, 2019. 19(11): p. 108.
3. Damas, F., C.A. Libardi, and C. Ugrinowitsch, The development of skeletal muscle hypertrophy through resistance training: the role of muscle damage and muscle protein synthesis. Eur J Appl Physiol, 2018. 118(3): p. 485-500.