Resistance Training under Caloric Restriction Enhances Muscle Maintenance

Resistance Training under Caloric Restriction Enhances Muscle Maintenance

Intro

I haven’t been actively writing for the blog mostly because my main focus is on the upcoming book. I always like to challenge conventional thinking and bro-science, as they keep getting louder and more powerful, ever promoting a vicious cycle.

I’m not sure how, but I stumbled upon this article from the late 80s which has been so far cited ~220 times (quite unpopular given its age).

Its been published in a reputable journal (AJCN) and it observed 40 obese women, randomly assigned to four different groups: control (C), diet without exercise (DO), diet + weight training (DPE), and weight training without diet (EO). The subjects were recruited for an 8-week weight-loss study [1].

Weight Lifting and Caloric Restriction

As pointed out by the researchers, there’s a trend of losing fat + muscle mass in weight loss studies when caloric restriction is being implemented, which is why it would be interesting to determine scenarios when lean mass loss is minimized or non-existent. They also pointed out some studies when such endeavor was achieved:

Negative caloric balance induced by exercise or in combination with caloric restriction appears to minimize losses of LBW. Zuti and Golding [2], Weltman et al [3], Rath and Slabochova [4], and Buskirk et at [5] all reported maintenance of LBW with exercise compared with diet-only controls.

The studies mentioned above (you can find them in the resources section) have used aerobic exercise, which, as the researchers observe, is not known to lead to gains in lean body mass. The challenge was to see if resistance weight training would lead to increases in lean body mass during caloric restriction, fact which was already seen happening in animal studies [1]:

Moreover, while it has been demonstrated in animals that regional muscular hypertrophy can occur during calorically induced weight loss and even starvation (1 3, 14), this has not been shown for humans.

Of course it has not been shown for humans at that time. Caloric restriction is uncool. It usually leads to increased hunger, bad mood, and cold limbs among others (not if you’re keto-adapted). Plus, the power of the supplement industry and bro-science were almost always dictating the trend. If you don’t train 3-4 times a week 1-2 hours every session and if you don’t consume a ton of protein, you will lose muscle and you will die (please excuse my sarcasm).

In this particular study we’re talking about obese women, not the optimal condition to observe physiologic changes as it may not translate well to lean individuals. But anyway, we can derive good insight from any study, given it being well or poorly conducted.

Subjects’ baseline energy requirements were calculated at 2,200-2,500 kcals per day and then reduced by 1,000 kcals for the calorie restricted groups.

I personally do not like the way their dietary protocol was formulated mostly because they had to consume 50% carbs, 27% protein and 23% fat. I think that different macronutrient partitioning protocols can elicit different metabolic and hormonal adaptations. They also included a protein supplement. 27% protein intake seems quite-high from my personal perspective.

The subjects in the control (C) and exercise only (EO) groups had to keep eating their normal diets with their usual energy intake.

As for the exercising protocol, the subjects from EO and DPE had to do resistance training 3 times a week. Each session included:

– bench press
– inverse leg press
– lateral pulldown
– biceps curls
– triceps extension
– calf raises
– leg extension
– hamstring curl

They had to do 3 sets of each exercise: the first 2 sets consisting of 10 repetitions, while the last set required doing repetitions to failure. Once the subjects were able to complete more than 12 repetitions in the third set, resistance (load) had to be increased. I suspect they were shooting for anaerobic training.

As one can see below, the biggest change in bench press 1RM was in the DPE group. Remember they were consuming 1,000 less calories compared to baseline.

Resistance Training under Caloric Restriction Enhances Muscle Maintenance - Bench Press 1RM

Body composition changes:

Resistance Training under Caloric Restriction Enhances Muscle Maintenance - Body Comp Changes

Some interesting, yet not surprising, observations. The biggest loss in weight was seen in the DO group (-4.47 ± 0.45 kg) and the biggest lean mass gain in the EO group (1.07 ± 0.25 kg).

DPE was the group were the subjects were able to increase lean body mass (0.43 ± 0.26 kg) and had the biggest reduction in fat mass (-4.32 ± 0.38 kg). This is what I call efficient body recomposition. Had these subjects have their dietary protocol optimized away from a high-carb regimen, I suspect results would’ve been even more significant.

The increases in total LBW support this possibility the protein supplement helped ensure sufficient protein intake to allow muscle growth to occur.

It may have helped indeed due to the possible concomitant activation of IIS (Insulin + IGF-1) and mTOR which support hypertrophy among others. Yet, it’s not the only way to do it.

In conclusion, data from this study indicate that weight training added to a caloric restriction program results in maintenance of LBW 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. There is no interaction between diet and exercise treatments with regard to weight loss.

Conclusions

I have yet to find a study that I could not attribute any flaw. And I may not find such study. Nothing wrong with that. There are many good points to be taken from this old study, while we should derive conclusions and lessons from its bad points.

What I am eager to see is studies conducted on healthy lean adult subjects following a well formulated low calorie high-fat (60%-70%), low protein (15%-25%), very-low-carb (10-15%) ketogenic protocol (keto-adapted would be even better) doing resistance weight training in comparison with other significantly different protocols.

This would be similar to my n=1 and it would allow us to observe the possible strong metabolic adaptations across different subjects. If you happen to know a study of this kind, please let me know in either of the comment sections below.

Resources

1. Ballor, D. L., Katch, V. L., Becque, M. D., & Marks, C. R. (1988). Resistance weight training during caloric restriction enhances lean body weight maintenance. The American journal of clinical nutrition, 47(1), 19-25.

2. Young, C. M., Scanlan, S. S., Im, H. S., & Lutwak, L. (1971). Effect on body composition and other parameters in obese young men of carbohydrate level of reduction diet. The American journal of clinical nutrition, 24(3), 290-296.

3. Weltman, A., Matter, S., & Stamford, B. A. (1980). Caloric restriction and/or mild exercise: effects on serum lipids and body composition. American Journal of Clinical Nutrition, 33(5), 1002-1009.

4. Rath, R., & Slabochova, Z. (1964). Changes of Body Composition in the Obese Subjected to Different Types of Reducing Regimens (Preliminary Communication). Annals of Nutrition and Metabolism, 6(4), 273-278.

5. Buskirk, E. R., Thompson, R. H., Lutwak, L., & Whedon, G. D. (1963). Energy balance of obese patients during weight reduction: influence of diet restriction and exercise. Annals of the New York Academy of Sciences, 110(2), 918-940.

Photo: The American Journal of Clinical Nutrition

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