Protein Amount and Post Workout Protein Synthesis – Research Review

MacNaughton et. al. The response of muscle protein synthesis following whole-body resistance exercise is greater following 40 g than 20 g of ingested whey protein.  hysiol Rep, 4 (15), 2016, e12893

The currently accepted amount of protein required to achieve maximal stimulation of myofibrillar protein synthesis (MPS) following resistance exercise is 20–25 g. However, the influence of lean body mass (LBM) on the response of MPS to protein ingestion is unclear. Our aim was to assess the influence of LBM, both total and the amount activated during exercise, on the maximal response of MPS to ingestion of 20 or 40 g of whey protein following a bout of whole-body resistance exercise. Resistance-trained males were assigned to a group with lower LBM (≤65 kg; LLBM n = 15) or higher LBM (≥70 kg; HLBM n = 15) and participated in two trials in random order. MPS was measured with the infusion of 13C6-phenylalanine tracer and collection of muscle biopsies following ingestion of either 20 or 40 g protein during recovery from a single bout of whole-body resistance exercise. A similar response of MPS during exercise recovery was observed between LBM groups following protein ingestion (20 g – LLBM: 0.048 ± 0.018%·h−1; HLBM: 0.051 ± 0.014%·h−1; 40 g – LLBM: 0.059 ± 0.021%·h−1; HLBM: 0.059 ± 0.012%·h−1). Overall (groups combined), MPS was stimulated to a greater extent following ingestion of 40 g (0.059 ± 0.020%·h−1) compared with 20 g (0.049 ± 0.020%·h−1; P = 0.005) of protein. Our data indicate that ingestion of 40 g whey protein following whole-body resistance exercise stimulates a greater MPS response than 20 g in young resistance-trained men. However, with the current doses, the total amount of LBM does not seem to influence the response.

Introduction

So first let me thank Brad Schoenfeld for making me aware of this paper.  It’s quite timely given that I’m currently mired (yes, mired) in the around workout nutrition chapter of the woman’s book.  Now, in recent years, the whole post-workout nutrition thing (or more generally around workout or peri-workout nutrition) has become a little bit more confusing than it was originally.

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A Comparison of Strength and Muscle Mass Increases During Resistance Training in Young Women

Chilibeck PD et. al. A comparison of strength and muscle mass increases during resistance training in young women. Eur J Appl Physiol Occup Physiol. 1998;77(1-2):170-5.

Strength gains with resistance training are due to muscle hypertrophy and nervous system adaptations. The contribution of either factor may be related to the complexity of the exercise task used during training. The purpose of this investigation was to measure the degree to which muscle hypertrophy contributes to gains in strength during exercises of varying complexity. Nineteen young women resistance trained twice a week for 20 weeks, performing exercises designed to provide whole-body training. The lean mass of the trunk, legs and arms was measured by dual energy x-ray absorptiometry and compared to strength gains (measured as the 1-repetition maximum) in bench press, leg press and arm curl exercises, pre-, mid- (10 weeks) and post-training. No changes were found in a control group of ten women. For the exercise group, increases in bench press, leg press and arm curl strength were significant from pre- to mid-, and from mid- to post-training (P < 0.05). In contrast, increases in the lean mass of the body segments used in these exercises followed a different pattern. Increases in the lean mass of the arms were significant from pre- to mid-training, while increases in the lean mass of the trunk and legs were delayed and significant from mid- to post-training only (P < 0.05). It is concluded that a more prolonged neural adaptation related to the more complex bench and leg press movements may have delayed hypertrophy in the trunk and legs. With the simpler arm curl exercise, early gains in strength were accompanied by muscle hypertrophy and, presumably, a faster neural adaptation.

Background

I haven’t done a research review in a fairly long time since I think I found it more useful to write articles and just link out.  Two weeks ago when I was babbling about neural adaptations to training, I mentioned a paper suggesting that more complex movements might cause slower increases in muscle growth.

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Dietary Restraint and Cortisol Levels – Research Review

I don’t think I’ve done a research review in a while and even though I imagine some visitors to the site may be getting tired of topics related to the book I’m working on, well, that’s what I’m currently working on so it’s kind of at the top of my mind right now.

Today, I want to do a research review but for various reasons, mainly the abstract being too long to paste, I want to do it a little bit differently. The paper I want to look at is titled

McLean JA et. al. Cognitive dietary restraint is associated with higher urinary cortisol excretion in healthy premenopausal women. Am J Clin Nutr. 2001 Jan;73(1):7-12. And you can get the free full text here.

Background

I imagine most visitors to my site are familiar with the hormone cortisol, even if many aren’t quite clear on what it does. Cortisol is often thought of as a “bad” hormone but this is too simplistic; what cortisol does in the body depends on a host of factors. The primary of these is whether it is released in a pulsatile and acute fashion (basically small pulses) or is elevated chronically. The first situation tends to be adaptive, the second tends to cause problems (for more details check out my still favorite book Why Zebras Don’t Get Ulcers by Robert Sapolsky).

So while acute pulses of cortisol help to mobilize fat, stimulate immune system function and improve memory, chronically elevated levels of cortisol may cause fat storage (especially in the face of high insulin), depress immune system function and harm memory. Basically, acute increases (that go down afterwards) are good, chronic increases (from chronic stress) are bad.

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Impact of the Menstrual Cycle on Determinants of Energy Intake – Research Review

L Davidsen et. al. Impact of the menstrual cycle on determinants of energy balance: a putative role in weight loss attempts. International Journal of Obesity (2007) 31, 887-890

Abstract: Women’s weight and body composition is significantly influenced by the female sex-steroid hormones. Levels of these hormones fluctuate in a defined manner throughout the menstrual cycle and interact to modulate energy homeostasis. This paper reviews the scientific literature on the relationship between hormonal changes across the menstrual cycle and components of energy balance, with the aim of clarifying whether this influences weight loss in women. In the luteal phase of the menstrual cycle it appears that women’s energy intake and energy expenditure are increased and they experience more frequent cravings for foods, particularly those high in carbohydrate and fat, than during the follicular phase. This suggests that the potential of the underlying physiology related to each phase of the menstrual cycle may be worth considering as an element in strategies to optimize weight loss. Studies are needed to assess the weight loss outcome of tailoring dietary recommendations and the degree of energy restriction to each menstrual phase throughout a weight management program, taking these preliminary findings into account.

 

Background

Amusingly, given the project I am currently finishing up (I promise, it’s coming along), I had run this piece back in 2009.  But since I am currently at a loss as to what to write about today, it seemed appropriate to run it again.  And yes, all of this will be covered in detail in the upcoming book along with ways to address and/or fix it.

Compared to men, women get the short end of the stick in almost everything related to body composition. Their bodies fight back harder, they lose both weight and fat slower (even given an identical intervention), they gain muscle more slowly, etc.  Then again, they do get that whole multiple orgasm thing so there is at least some good that comes along with the bad.

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Reduced Fat and Reduced Carbohydrate Diets and Fat Loss – Research Review

Hall, KD et. al. Calorie for Calorie, Dietary Fat Restriction Results in More Body Fat Loss than Carbohydrate Restriction in People with Obesity Cell Metabolism  Cell Metabolism (2015) 22: 1–10.

Abstract

Dietary carbohydrate restriction has been purported to cause endocrine adaptations that promote body fat loss more than dietary fat restriction. We selectively restricted dietary carbohydrate versus fat for 6 days following a 5-day baseline diet in 19 adults with obesity confined to a metabolic ward where they exercised daily. Subjects received both isocaloric diets in random order during each of two inpatient stays. Body fat loss was calculated as the difference between daily fat intake and net fat oxidation measured while residing in a metabolic chamber. Whereas carbohydrate restriction led to sustained increases in fat oxidation and loss of 53 ± 6 g/day of body fat, fat oxidation was un- changed by fat restriction, leading to 89 ± 6 g/day of fat loss, and was significantly greater than carbohydrate restriction (p = 0.002). Mathematical model simulations agreed with these data, but predicted that the body acts to minimize body fat differences with prolonged isocaloric diets varying in carbohydrate and fat.

Background on Reduced Fat and Reduced Carbohydrate Diets

For years the debate over reduced fat or reduced carbohydrates has gone on and it shows no sign of stopping.  The pendulum has actually swung over the years.  In the 70’s, the Atkins diet drove interest in very low/reduced carbohydrate diets.  In the 80’s, reduced fat diets came into vogue as it looked like dietary fat was more easily stored as body fat and it looked like, so long as fat intake was kept low enough, weight and fat loss would happen (this was true until people went nuts and started overeating low fat foods in excess).  In the 90’s, somehow the Zone caught on and then things started to fragment.  Cyclical ketogenic/reduced carbohydrate diets became popular and I even wrote an entire book on the topic.

But now, with the joys of the Internet, the entire dietary world has become very divided.  With the publication of a book that I shall not name the idea that insulin was the cause of obesity, that reducing insulin was either required or would magically cause fat loss came back into vogue.  Nevermind that the entire insulin hypothesis has been completely destroyed.

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