Diet, weight loss and body composition changes

This is an unfortunately long post, and I apologize for it, but the reason is that I find all this so darn interesting.  Hope you do to.

A little while back I looked closer at some of the science behind diet, weight loss and body re-composition. I have heard people say on several occasions that a low carbohydrate diet will prevent loss of muscle mass and that all weight lost is fat. So I wanted to find out once and for all what really happens with our body when we lose weight. I’ll show you some of the data, and although these studies are not the only ones, I am confident that the studies presented here give a satisfactory accurateness

So there is much debate about what happens to our body composition when we lose weight and perhaps especially when we do it using a low carbohydrate diet. This quote is from Sachiko T. et al 2001. Dietary Protein and Weight Reduction: A Statement for Healthcare Professionals From the Nutrition Committee of the Council on Nutrition, Physical Activity, and Metabolism of the American Heart Association:

Some popular high-protein/low-carbohydrate diets limit carbohydrates to 10 to 20 g/d, which is one fifth of the minimum 100 g/d that is necessary to prevent loss of lean muscle tissue.

Clearly the AHA suggests that we will lose muscle tissue by going low carb. In my school we used the exercise physiology textbook from McArdle, Katch and Katch (2007) which said this:

…low carbohydrate diet sets the stage for a significant loss of lean tissue as the body recruits amino acids from muscle to maintain blood glucose via gluconeogenesis.

Once again, low carbohydrate dieting does not seem a good idea if we want to preserve muscle mass while we lose fat mass.

But the questions remains unanswered; how much muscle mass do we lose if we go low carb and can we do anything to prevent a potential loss of muscle tissue?

Let us look at some studies and see what they tell us.

This study from Bonnie Brehm and coworkers compared a low carbohydrate diet to a low fat diet:

All participants in the above study were women and they were obese. Dietary energy content was reduced in both diets and body composition was measured using Dual Energy X-ray Absorptiometry (DEXA). As you can see, weight loss was greater with low carb, but so was loss of lean body mass (LBM) and the percentage loss of LBM was not much different between diets. 
Here’s another study:
This was a crossover study where all the participants tried two different diets in random order. The results are given under:
As is usually the case in weight loss trials, the men lost more weight than the women. And once again low carb caused a greater weight loss, but also quite the loss of lean body mass. The women eating low fat seemed to lose the greatest percentage LBM, which is also a recurrent theme in weight loss trials. 
Next, here’s Kelly Meckling and coworkers:
One of the goals in this study was for the low fat group to reduce their calorie intake to the naturally reduced level of the low carbers. Weight loss did not differ between groups, but loss of LBM was significantly larger in the low carb group and over 25% of the LC weight loss was lean body mass. Body composition was measured using bioelectrical impedance analysis (BIA).
Next, as study from William Yancy and coworkers from 2004:
Weight loss with low carb was double that of low fat and this time loss of fat free mass (FFM) was actually quite larger in the low fat group. LBM is what is left if we remove fat mass and skeletal mass. Fat free mass is, not surprisingly, total mass minus fat mass. LBM and FFM are used interchangeably. 
It seems that loss of non-fat mass is common, regardless of diet, but we need to look at some more studies to get a clearer picture.
Here’s one from down under, from Manny Noakes:
This is a short study, but with 83 participants. The results are pretty similar, both when it comes to weight and LBM loss, but in both diets around 30% of the lost weight was LBM and that is rather much.
Another one from Australia. Here’s Jennifer Keogh and coworkers:
Both diets were 30% energy restricted and designed to be isocaloric. Once again there was a significant loss of fat free mass with both diet strategies.
Jeff Volek brought us this study in 2008:
An Atkins type diet was compared to a regular calorie restricted low fat diet in 40 men and women. Weight loss was greater with low carb, but so was loss of LBM. So far, there seems to be little truth to any claim that low carb preserves LBM.
This next one is another crossover study:
Alexandra Johnstone and coworkers showed us yet again that weight loss is greater with low carb, but that so is loss of FFM. Notice that this is a study of men only and so the percentage loss of FFM is much smaller than in studies of women.
One last study. Third one from Australia, this time by Grant D. Brinkworth:
118 people participated in this eight week study and were scanned with DEXA. Weight loss was greater with low carb and both groups lost about 20% FFM.
To summarize, loss of fat mass is greater with LC than LF diets. Loss of LBM is common on both LF and LC diets, but as we will see, not obligate. But there are some considerations to make first.
First of all, any loss of water will usually be considered LBM and so if there is a difference in water loss between diets, this will affect loss of LBM/FFM. Carbohydrate restriction usually does cause a greater loss of body water, at least in the initial phase of the diet. Loss of glycogen with low carb will cause a parallel loss of water and so there is reason to expect a larger loss of LBM with low carb, and we need to remember that LBM is not a measure of muscle proteins.  
Contradictory findings
Although loss of LBM is clearly common on low carb diets, there are studies suggesting that such a loss can be avoided.
In a very small crossover study by Benoit et al from 1965 we can see the obvious advantage of low carb dieting compared to fasting:
Notice the difference in LBM loss. One likely advantage of carbohydrate restriction is that the combination of adequate protein intake and high ketone body production spares muscle proteins from being used to produce glucose. The Benoit study is small, but it suggests that loss of LBM is not a necessary consequence of low carb dieting.
And look at this one:
In this study of twelve men, LBM increased during the diet period, even though there was no change in the exercise pattern of the subjects. It is results like these, which sometimes appear, that suggests that it is possible to lose weight in a way that spares muscle tissue. In another very small study of very obese adolescents, similar results were found:
After eight weeks of a very low calorie ketogenic diet, lean body mass increased by almost 1,5kg while 15kg of fat was lost.
So I think it’s time to ask what the difference between these few studies where LBM increases (in spite of water loss) and the RCT’s where a low carbohydrate diet always leads to some LBM loss. But remember also that not all LBM is functional LBM. That is, we expect some loss of LBM and some LBM can be lost without negative consequences. We must remember to keep our feet on the ground, there is no problem with some loss of LBM with large losses of fat mass.
To make a long story short, there are some important factors we can manipulate in order to reduce loss of LBM. Being a man is perhaps the most effective. Men lose more fat and less LBM when they lose weight. It’s just the way it is. But both men and women can increase their protein intake. In many of the RCT’s in this post, average protein intake was low, often around 1g/kg body weight/day. The optimal intake is probably closer to 1.8g/kg/day (severely overweight people should use ideal body weight instead of actual body weight).
Several studies have found a correlation between protein intake and LBM loss. James Krieger wrote this in 2006:
And he concluded thusly:
In a very recent review article, Stuart Philips and Luc van Loon has this to say:
The thing with carbohydrate restriction is that is causes a greater fat loss and greater LBM loss than low fat strategies, but the end result is that low carb thus causes a greater reduction in body fat percentage and so the greater change in body composition. To optimize the results, protein intake should most likely be kept at >1,5g/kg/day. Here’s another quote from Phillips and van Loon:

There is also the matter of sodium and potassium that might play a part in the results. Potassium is an important intracellular ion in our muscles and adequate potassium is important for creating an anabolic environment. The trouble with ketosis or severe carbohydrate restriction is that it causes our kidneys to excrete sodium and unless that sodium is properly replaced the kidneys compensate by excreting potassium. In short, when optimal body composition changes is the goal, or optimal performance, salt intake is important and should be a good deal higher than the daily recommended intake.

In addition to minding our protein and salt intake, we can of course also do resistance exercise in order to increase lean mass retention or even increase lean mass while reducing fat mass. It is, not surprisingly, well documented that resistance exercise, as a part of weight loss, is very effective at reducing lean mass loss, regardless of diet. But in order for resistance exercise to yield optimal results, protein and salt intake must be optimized.  
Richard Wood and coworkers just published results from a study where overweight older men were put on two different diets with or without resistance exercise. Here are the results:
Even though the results favor both low carbohydrate dieting and resistance exercise, I must say that I was surprised at the amount of FFM loss in the low carbohydrate and resistance exercise group, even when considering that some is water loss. After 12 weeks I would have suspected FFM to have increased. But there are once again some factors to consider. First of all, the mean age of the participants were 60 years. This may have caused the results to be smaller than if younger men participated. Also the resistance exercise was not very heavy, it could have been a good deal heavier and it is likely that muscle hypertrophy would then have been greater.
Donald K. Layman and coworkers compared the effects of two different diets varying in protein and carbohydrate content, with or without resistance exercise. The graphs on the left are women and the ones on the right are men:

Clearly, both increasing protein/decreasing carbohydrate and resistance exercise improve body composition changes. The low carbohydrate diet in this study was not very low. Average carb intake during the intervention was 141g in LC and 126g in LC+RE. Protein intake was 110g and 102g respectively.

I’d like to compare the results of a study I conducted in 2010 with that of a study from Donnely from 1991:

These are two very different strategies. In our study the participant were told to be in dietary ketosis, but could eat as much as they liked. In Donnely’s study calories was severely restricted. Also in our study the participants exercised twice a week, whereas in Donnely’s they exercised four times per week (resistance exercise). They are both effective strategies both for losing weight and changing body composition, so it is up to us what we prefer. I for one would like to eat as much as I please and not have to exercise that much to get the results I want.

The conclusion
Loss of LBM with weight loss is common but not obligate. A low carbohydrate diet is no grantee for all weigh loss being fat. In order to achieve optimal body re-composition one should reduce carbohydrates, make sure to eat enough protein and salt, and do regular heavy resistance exercise. The results one can achieve are quite astonishing.

What is the best exercise for fat loss? Part IV

The bias
I have this theory. In the last post I concluded that there is sufficient data for recommending high intensity exercise in favor of low intensity for fat loss. Admittedly, the data in support of this is not strong. It is there, but I would not bet my life on it yet.

I might be a bit biased in favor of high intensity because of my theory that seems rigidly stuck in my brain. From the world of resistance exercise, we know that you can use a number of strategies to build muscles. Some use slow movements with relatively low resistance where the muscles are activated for a long time. Others use quick movements with high loads allowing for a greater workload to be performed in a shorter amount of time. Some simply cut blood flow to the working muscles which also will make them grow. The bottom line is that the one important factor when it comes to muscle hypertrophy seems to be the amount of physiologic stress placed on the working muscles during exercise. So you can stress a muscle or muscle group by making it work for a long time like in static strength training or you can do the standard high load high repetition fast movement exercise. You can even do pure eccentric exercises rather than the usual concentric/eccentric. All of this and pretty much everything in between will cause muscle growth. It is the total workload, the time multiplied by load, that matters.

The concept is very similar to the energy hypothesis that claims it is the amount of energy spent during exercise that determines fat loss, rather than intensity or time by itself. The difference is that the hypertrophy theory is supported by science whereas the energy hypothesis is not.

Although hypertrophy can be achieved in many ways, there is a limit to the equation, workload = time x load. It is not only the amount of work done that determines muscle growth. Running, for example will not build significant amounts of muscle even if some of the muscles involved perform a great workload. The reason is that somewhere in the area between multiple repetition resistance exercise and endurance exercise the stimulus changes and thus the physiological adaptations.

Most people are aware of this and know that walking or running is a poor strategy for building muscles.

My theory is that the whole «exercise intensity and fat loss» issue is of a similar nature, that to a certain degree, it is the amount of work performed that matters the most. Both low and high intensity exercise cause fat loss, but somewhere in the declining intensity area the stimulus becomes different and fat loss is reduced. Shopping, gardening and other everyday activities with low intensity, but often of long duration seem poor strategies for weight loss. Likely, we are working to close to the body’s comfort zone to make it adapt. Or put in better words, the body does not adapt to these activities because it doesn’t need to, it already has.

This means that high or low intensity might not matter that much, as long as the tissues are exposed to new stimuli, forcing them to adapt. However, this is not to say that high intensity is not better than low, the question is how much better.

As with muscle hypertrophy, if the goal is to maximize all factors, then high intensity, high workloads and variation in stimuli is important. I believe it is the same with exercise intensity and fat loss. This might explain some of the variation in results found in different trials.

The losing of fat and not muscles
Loss of muscle mass is common with weight loss, independent of dietary approach. Some diets seem to lead to better muscle mass retention and some exercise forms will prevent muscle loss. But we must make sure not to assume that all muscle loss is a negative thing. The size of our muscles will determine our appearances while their function is what will affect our health.

In school I was taught that one important factor for skeletal muscle hypertrophy was positive energy balance. You had to take in more than you expended. This however, turned out to be wrong. The muscles might need a readily supply of fuel, but they couldn’t care less if the energy comes from glycogen and fat stores or from food. Thus it is theoretically possible to lose fat mass while increasing muscle mass.

Fleck and Kraemer [1] concludes that in untrained individuals doing regular resistance exercise you can expect a 2kg increased muscle mass in 14 weeks. That’s about 0.06kg per exercise session. If we consider the women only trials the number is about 0.04kg per session.

Resistance exercise builds muscles when we’re not dieting, but does this hold true when we are simultaneously losing fat mass? Short answer, yes. We can. But, you would not come to that conclusion if you put together a meta-analysis of decent trials. The reason is that in several studies fat loss is significant while muscle growth is not. However, when the mean is zero change, the individual data will show that many did increase their lean mass while losing fat.

I know this is a statistical quagmire, but part of my conclusion will still be based on individual results rather than the reported means. The reason is that when several people in a resistance exercise study build muscle, it is very likely that the exercise is to blame. This is not a strategy I would use when for example looking at weight loss results from low fat diet studies that show a mean zero improvement. If finding that half the participant lost weight and the other half did not, it would not be smart to claim that low fat diets works. There are a great many things that lead us to lose weight, although it almost always involves some reduction in dietary carbs. But as I said, when people gain muscle in a resistance exercise trial, the gain is extremely likely to come from the resistance exercise.

There is another issue as well. Many body composition studies are done with DEXA (dual energy x-ray absorptiometry). Because adipose tissue mass is considered 85% lipid and 15% water, and because DEXA measurement of fat free mass includes this adipose tissue water, a loss of adipose tissue without loss of fat free mass suggests favorable changes in muscle mass.

When I did a small study in 2009 I found that in eight women who did regular resistance exercise in combination with a ketogenic diet, four of them increased lean body mass, while four reduced it. The study was not large enough to indicate what factors were responsible for the lack of muscle mass gain in the other four. I guess anything from dietary protein (amino acids), thyroid issues to stress might contribute [2]. 

Figure 2 from Jabekk et al 2009. Lc+Ex= Low carb + resistance exercise. Ex=resistance exercise.
Shadid and Jensen [3] compared 20 weeks of pioglitazone with exercise and diet. Diet and exercise resulted in 11.8kg mean weight loss. The group was instructed in a 500kcal deficit diet and in an exercise program starting with 15min of aerobic exercise three times per week at 50% of each individual’s heart rate reserve. This was gradually increased to 45min aerobic exercise four times a week at 60–70% of heart rate reserve. The surprising find in the study was that the intervention caused a mean 9.5kg fat loss and a non significant 0.5kg reduction in fat free mass, which is an unusually small reduction.

Barbara A. Gower et al [4] also got surprisingly good results from a traditional very low energy diet in overweight women. Mean fat mass lost was 11.2kg. White women in the trial lost a non significant 0,77kg lean mass while the African American women lost 1.53kg (non significant) lean mass.

In both the above trials, several individuals managed to increase their lean mass while reducing fat mass. This was even done without any reported resistance exercise. Most if not all of the participants in the trials were insulin resistant, which if improved, I suspect can cause muscle growth by itself.

Gary Hunter [5] who coauthored the Gower trial found that in women who lost 12kg of weight, resistance exercise conserved lean mass. The women were randomized to diet only, diet and resistance exercise or diet and aerobic exercise.

Figure 1 from Hunter et al 2008. FFM=fat free mass. AA=african-american. EA=european-american
In a study from 1988 Douglas L. Ballor et al [6] concluded similarly to Hunter and stated that “In conclusion, data from this study indicate that weight training added to a caloric restriction program results in maintenance of LBW [Lean Body Weight] and regional increases in muscle area. When diet plus weight-training exercise is compared with exercise without caloric restriction, there is no difference in the rate of strength gain or magnitude of upper-arm muscle area increase.» 
From Ballor et al 1988. C=control. DO=diet only. DPE=diet plus exercise. EO=Exercise only. 
It might seem counterintuitive, but finding that endurance exercise increases lean mass or attenuate lean mass loss is quite common. Janssen et al [7] found that aerobic and resistance exercise did equally well in preserving muscle mass with dieting in premenopausal obese women. This finding reflected their previous (1999) trial with both men and women, which also found preservation of lean mass with both resistance and aerobic exercise.

Contrary to Janssen et al, Geliebter et al [8] and Bryner et al [9] did find that resistance exercise was more effective in improving lean mass with weight loss than aerobic exercise.

The combination of resistance training with aerobic training has been shown to be superior for body weight and fat loss and to result in greater lean body mass compared to aerobic exercise alone in several randomized controlled trials.

Park et al [10] for example, found that aerobic exercise reduced fat percentage by 9.2 while combining it with resistance exercise reduced fat percentage by 10.3. Lean mass increased by 0.9kg with aerobic exercise and by 5.6kg with combined exercise. This trial did not use a dietary intervention and the subjects had a mean BMI of 25. But it is an interesting example of how the exercise did not cause a weight change but still caused a significant body composition change.

Using a combination of high protein diet and resistance exercise Wycherley et al [11] demonstrated an 11.4kg fat mass reduction in 16 weeks. The reduction was accompanied by a 2.4kg reduction in fat free mass. The body composition results are impressive, but as I said we rarely if ever find a significant mean fat loss in combination with significant mean fat free mass gain.

Saving the best for last, Kevin David Ballard and colleagues is responsible for a meeting abstract from 2008 titled “Effects of diets restricted in fat and carbohydrate with and without resistance training on body composition and cardiovascular risk.” Ballard reports results from the Department of Kinesiology at University of Connecticut were heavyweights like Jeff Volek and William Kraemer reside. They report having examined the effects of carbohydrate restricted (CRD) and low fat diets (LFD) alone and in combination with resistance training (RT) in 47 overweight men.

The results state that “Reductions in body mass, fat mass, percent body fat and abdominal fat were greater in the CRD than the LFD (p<0.001).” and that “Gains in lean body mass were demonstrated in the RT groups only (p=0.004).” Their conclusion: “Resistance exercise is an effective strategy to combat diet induced losses of lean body mass.

On the matter of resistance exercise and fat-free mass Donnely and ACSM [12] concludes thusly: “…most studies combining resistance training with energy restriction report improved lean body mass compared to dieting alone.” They continue; “In summary, resistance training does not seem to be effective for weight reduction in the order of 3% of initial weight and does not add to weight loss when combined with diet restriction. Resistance training increases fat-free mass when used alone or in combination with weight loss from diet restriction. Resistance training may increase loss of fat mass when combined with aerobic exercise compared to resistance training alone.

Petra Stiegler and Adam Cunliffe [13] did a very good job addressing the evidence for the effect of exercise and diet on anthropometric variables. They conclude that: “…it becomes clear that a combination of modest caloric restriction combined with endurance exercise or endurance and physical training of different modes is preferable over dietary modification alone to induce favorable changes in body composition accompany ing weight loss.

The Conclusion 
It is possible to increase lean mass while losing fat mass. There are many factors at play but a high animal protein diet and resistance exercise is the best strategy we know of. Resistance exercise is very effective at increasing lean body mass, and it seems that this effect remains even if people are dieting and the effect is observed in both low and high carbohydrate diets. The addition of endurance exercise to diet and resistance exercise seems to slightly increase fat mass loss, but has little effect on lean mass.

The references

1. Fleck SJ, Kraemer WJ: Designing resistance training programs. Champaign, IL: Human Kinetics; 2004.

2. Jabekk PT, Moe IA, Meen HD, Tomten SE, Hostmark AT: Resistance training in overweight women on a ketogenic diet conserved lean body mass while reducing body fat. Nutr Metab (Lond) 2010, 7: 17.

3. Shadid S, Jensen MD: Effects of pioglitazone versus diet and exercise on metabolic health and fat distribution in upper body obesity. Diabetes Care 2003, 26: 3148-3152.

4. Gower BA, Weinsier RL, Jordan JM, Hunter GR, Desmond R: Effects of weight loss on changes in insulin sensitivity and lipid concentrations in premenopausal African American and white women. Am J Clin Nutr 2002, 76: 923-927.

5. Hunter GR, Byrne NM, Sirikul B, Fernandez JR, Zuckerman PA, Darnell BE, Gower BA: Resistance training conserves fat-free mass and resting energy expenditure following weight loss. Obesity (Silver Spring) 2008, 16: 1045-1051.

6. Ballor DL, Katch VL, Becque MD, Marks CR: Resistance weight training during caloric restriction enhances lean body weight maintenance. Am J Clin Nutr 1988, 47: 19-25.

7. Janssen I, Fortier A, Hudson R, Ross R: Effects of an energy-restrictive diet with or without exercise on abdominal fat, intermuscular fat, and metabolic risk factors in obese women. Diabetes Care 2002, 25: 431-438.

8. Geliebter A, Maher MM, Gerace L, Gutin B, Heymsfield SB, Hashim SA: Effects of strength or aerobic training on body composition, resting metabolic rate, and peak oxygen consumption in obese dieting subjects. Am J Clin Nutr 1997, 66: 557-563.

9. Bryner RW, Ullrich IH, Sauers J, Donley D, Hornsby G, Kolar M, Yeater R: Effects of resistance vs. aerobic training combined with an 800 calorie liquid diet on lean body mass and resting metabolic rate. J Am Coll Nutr 1999, 18: 115-121.

10. Park SK, Park JH, Kwon YC, Kim HS, Yoon MS, Park HT: The effect of combined aerobic and resistance exercise training on abdominal fat in obese middle-aged women. J Physiol Anthropol Appl Human Sci 2003, 22: 129-135.

11. Wycherley TP, Noakes M, Clifton PM, Cleanthous X, Keogh JB, Brinkworth GD: A high-protein diet with resistance exercise training improves weight loss and body composition in overweight and obese patients with type 2 diabetes. Diabetes Care 2010, 33: 969-976.

12. Donnelly JE, Blair SN, Jakicic JM, Manore MM, Rankin JW, Smith BK: American College of Sports Medicine Position Stand. Appropriate physical activity intervention strategies for weight loss and prevention of weight regain for adults. Med Sci Sports Exerc 2009, 41: 459-471.

13. Stiegler P, Cunliffe A: The role of diet and exercise for the maintenance of fat-free mass and resting metabolic rate during weight loss. Sports Med 2006, 36: 239-262.

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Meanwhile, in Japan

Felt like writing something about exercise. After all, my education is in exercise science and not nutrition. This is about an exercise trend from Japan. It might be the next big thing in both muscle building and physical therapy and it may hurt like hell.

This is Kaatsu training!

Simply speaking Kaatsu training is occlusion training or training where a large part of the blood flow to and from the exercising muscles are restricted by a cuff. Its purpose is to increase muscle size without having to use high resistance and heavy loads.

Increasing muscle size is dependent on a variety of factors, but the important point is that muscles grow due to adaptation to stress. The larger the stress the stronger the effect (to a certain point) and it is the total amount of physiological stress that stimulates muscle hypertrophyIncreasing total stress can be achieved by for example increasing resistance, reducing break time, increasing number of sets and also as it appears, restricting blood flow.

Kaatsu training consists of performing low-intensity training while a relatively light and flexible cuff much like the ones used to measure blood pressure, is placed on the arms or legs usually close to the trunk. Inventor of Kaatsu training, Yoshiaki Sato, has worked with Kaatsu for more than 40 years and is still going strong.

Kaatsu may be an important tool in rehabilitation. Yoshiaki Sato, then at the Department of Ischemic Circulatory Physiology at The University of Tokyo describes his own experience with Kaatsu training: “…witnessing an older wheelchair-bound individual regain the use of his legs as well as another individual regaining sensation…”

Yoshiaki Sato in the 60’s while experimenting with Kaatsu

Kaatsu training does require some caution because blocking blood flow too much may be deleterious and cause thrombosis. Mr. Sato was himself hospitalized in the 1960’s after exercising with constricted blood flow and disregarding an increasing numbness in his legs. He experienced an episode of acute shortness of breath and was hospitalized with a pulmonary embolism. Sato later patented Kaatsu and made guidelines to reduce the risk of overdoing it like he himself did.

From Abe et al 2005
From the beginning it was clear that blood flow constriction combined with resistance exercise gave some exercise advantage even at levels as low as 20% of 1 repetition maximum (RM). Several studies have found increased muscle size at exercise intensities far lower than what may cause muscle growth under normal conditions.

In 2005 Sato with Takashi Abe and Charles F. Kearns demonstrated effects at even lower intensities. They made 18 young men walk on a treadmill 2 times a day, 6 days a week for 3 weeks. They did 5 sets of 2-minute bouts with treadmill speed at 50 m/min, with a 1-min rest between bouts. 9 of these men walked with a cuff round their thighs restricting blood flow.

The Kaatsu group experienced higher growth hormone levels during exercise and by day 4 their muscle-bone cross sectional area was significantly larger than that of the control group. By week 6 it had increased 6% in the Kaatsu group and nothing in the control group. In the Kaatsu group mid thigh quadriceps cross sectional area increased by 5.7% while hamstrings increased 7.6%. Leg press and leg curl 1RM strength increased by 7.4% and 8.3% respectively in the Kaatsu walk group, but not in the control-walk group. 

These results may be of great significance for elderly and frail people. Normally, if you want to achieve significant muscle size increases you must exercise at high intensities and often with large external loads (>65% of 1 repetition maximum). These training intensities however may not always be possible in the elderly. Here the scientists showed that walking in a relatively slow tempo can build muscles. This is great news, because muscle wasting is a serious problem especially in the older part of the population and may cause great disabilities and need for care.

Yoshiaki Sato in his 60s still experimenting with Kaatsu
When exercising limbs have a restricted blood flow the physiologic stress increases and muscles grow more than non restricted muscles. But recent data also suggest that non restricted muscles in multi joint exercises may benefit from Kaatsu. A recent pilot study examined the effects of low intensity bench press with restricted blood flow on chest muscle and triceps hypertrophy.

10 men were divided into low intensity bench press with or without occlusion. The exercise consisted of bench press at 30% of 1RM, four sets of a total 75 reps, twice daily, 6 days a week for 2 weeks. By the end of two weeks triceps and pectoralis muscle thickness increased 8% and 16% respectively in the Kaatsu group while the number were -1% and 2% in the control group. 1RM bench press also increased significantly in the Kaatsu group only.

I won’t go into the mechanisms here, but they are still poorly understood. I was once a part of an occlusion exercise experiment where I had 7 biopsies taken from my vastus lateralis muscles. I think one of the things the researchers were looking at was heat shock proteins. Growth hormone secretion has been shown to be increased with occlusion, some have suggested (mostly on the basis of animal studies) that myostatin and cortisol may be involved. Other hormones and growth factors have been measured, but no single mechanism has stood out yet.

Several studies on occlusion training have, in addition to hypertrophy and increased strength found increased oxygen uptake. A recent Korean study found that 2 weeks of occlusion walking increased maximal oxygen uptake in trained athletes. 

Although I am uncertain of the importance of Kaatsu in sports and regular recreational exercise (it is rather uncomfortable when you feel your legs pumping, turning red, and going numb) it is definitely an interesting method that might prove an important tool in physical therapy both for older people and athletes recovering from injuries.

So if you want to do it like they do it in Japan, just strap yourself in!

Just a small reminder

”…low carbohydrate diet sets the stage for a significant loss of lean tissue as the body recruits amino acids from muscle to maintain blood glucose via gluconeogenesis.”
                          Exercise Physiology, Mcardle, Katch & Katch 2007
There is one aspect of human metabolism that is too often overlooked in the discussion of human nutrition and exercise metabolism. It is the simple fact that there are two energy sources for our cells. Energy from the food we eat and energy from energy stores in our body (glycogen and fat).
I am often met with the claim that muscles cannot hypertrophy if you are in a negative energy balance. I am willing to agree that the claim does seem plausible, but it is misunderstood. It is misunderstood because we have to view the energy situation from the muscles point of view.
The muscles do seem to require a positive energy balance to grow, but they require a local positive energy balance, not a whole body positive energy balance. Simply put, the muscles may have surplus energy even though we consume less energy than we expend, provided the energy stores give out enough energy.
Local cellular energy availability does not necessarily reflect whole body energy availability. This means that we can loose weight as fat while gaining muscle mass even if our body is in a negative energy balance.
Loss of muscle mass or lean body mass is common in weight reduction studies. The number is often as high as or higher than 30% of total weight lost. This is counterintuitive. The point of loosing weight when you are overweight is to lose fat not muscles.
It seems that in studies of low calorie diets that the muscles often lack the energy to maintain their size. In a recent study by Wycherley et al, 59 overweight persons with diabetes did calorie restricted diets combined with supervised resistance exercise 3 days a week. You would expect to see an increase in muscle mass from all this resistance exercise, but after 16 weeks the participants had lost on average 2kg of fat free mass.
To be fair, several studies have shown maintenance of fat free mass with weight loss from calorie restriction when combined with resistance exercise. But calorie restriction may not be the best way to tap into the body’s energy stores.
A low carbohydrate diet will increase the availability of the energy stored as fat. In addition, ketone bodies prevent a large use of proteins for glucose production. Contrary to what the quote at the start of this post claims.
In 2002 Volek et al  put overweight men on a 6 week diet with only 8% carbohydrate. The study caused an obvious decrease in fat mass, but in combination with a significant increase in lean body mass, without a resistance exercise intervention.
Willy et al put six overweight adolescents on a ketogenic diet and observed an average weight loss of 15.5kg in combination with 1,4kg increase in lean body mass. All in eight weeks.
Individual results in studies show that it is possible to markedly increase muscle mass while reducing fat mass. I’ve personally seen large reductions in fat mass in combination with more large increases in lean body mass from a combination of carbohydrate restriction and resistance exercise.
My point is that if muscles require a positive energy balance to hypertrophy, carbohydrate restricted diets offers an effective way of giving muscles the energy they need while reducing fat mass. Future studies will hopefully elucidate further.