LOSE FAT WITHOUT LOSING MUSCLE ARTICLE SUMMARY
- The best way to lose fat without losing muscle is a combination of high protein and resistance exercise.
- Dieting individuals need a higher ratio of EAAs to stimulate muscle protein synthesis than when not dieting.
- Resistance exercise preserves lean mass losses, whereas cardio will not.
- Weekly weight losses between 0.5-1% have been suggested as optimal; however, this depends on the amount of body fat starting the diet to determine the appropriate deficit.
LOW CALORIES LOWERS TOTAL TESTOSTERONE AND OTHER HORMONES
Low energy intake/low calories have long been known to disrupt endocrine, metabolic, and physiological dysregulation, resulting in the loss of lean muscle. The Female Athlete Triad and RelativeEnergy Deficiency in Sport (RED-S) syndromes describe the effects of chronic low energy availability on health and performance outcomes.
Total calories dictate the metabolic consequences of weight loss. In conjunction with resistance exercise, high-protein diets can prevent the loss of lean muscle, but if the caloric restriction is too low, not even high protein will not completely prevent muscle loss.
Large caloric deficits in conjunction with rapid rates of weight loss (>1 kg/per week or 2.2 pounds per week), which would require a caloric deficit of ~1,000 calories per day, are associated with a greater propensity for lean mass loss and potential declines in performance.(7)
THE ROLE OF TESTOSTERONE
In a study of male combat sports athletes, keeping calories at 20 kcal/kg/fat-free mass per day with a high protein diet was sufficient to reduce body fat and body weight without reductions in testosterone hormone levels or losses in lean muscle mass. However, when the athletes dropped calories to <10 kcal/kg/fat-free mass, they experienced reductions in decreased testosterone and losses in muscle.(8)
HIGH PROTEIN: LOSE FAT WITHOUT LOSING MUSCLE
The best example of adequate calories being inadequate comes from studies of soldiers undergoing combat training simulations. They can be provided with high-protein diets and perform vigorous exercise, but they will lose weight and lose muscle mass if the calorie deficit is too low. Soldiers consumed 5 kcal/kg/fat-free mass during intense combat training.
High protein supplementation after severe caloric restriction did not enhance the restoration of lean mass above those eating ~ 2 g/kg/bw. (i.e., 1.1 grams of protein per pound of body weight)(9) It has also been found that prolonged calorie deficits <25 kcal/kg/FFM is the threshold for bodybuilders while dieting to prevent muscle loss.(10)
Dr. Helms, in his book the Muscle and Strength Pyramid: Nutrition, recommends that women should try and stay above 30 kcal/kg/LBM (~13.6 kcal per pound of lean mass) and men stay ~25 kcal/kg/LBM (~11.4 kcal/lb/LBM).(11)
LOW CALORIES REDUCE TESTOSTERONE
Low energy availability can also result in a reduction in testosterone. Many factors can influence hormone levels, and dietary fat and testosterone are connected to lean mass. Low energy availability has decreased both luteinizing hormone (i.e., a hormone produced in the brain that signals the testes to produce testosterone) and testosterone.
For example, study participants were categorized as having low energy availability (<30 kcal/kg/FFM/day) and had significantly lower testosterone levels than those that were classified as a moderate energy availability (30-45 kcal/kg/FFM/day).(12)
A high testosterone diet plan needs adequate calories for normal testosterone functioning. A testosterone meal plan should raise calories back to slightly higher maintenance levels after dieting. There is some truth to the eggs & steak testosterone boosting effect, which can be attributed to the rich source of protein, fats, and calories. Fear not. Low-carb diet and testosterone levels can be maintained for those on low-carb diets.
LOSE FAT WITHOUT LOSING MUSCLE: The Importance of High Protein
The higher the protein intake, the lower the chance of lean muscle loss. However, if the caloric deficit is large enough, high protein will only partially prevent losses of lean muscle mass. Resistance exercise is the key to maintaining lean muscle mass while dieting. A six-week high protein diet alone (2.8 g/kg/bw or 1.3 grams per pound of bodyweight) was not able to prevent lean muscle loss during a moderately calorie-restricted diet.
Lean mass accounted for 47% of the weight loss. (13) In a study of rowers, a 6% body weight loss over 8 weeks resulted in 50% of their lean mass. The authors suggested that the very low body fat of the athletes starting the diet rapidly accelerated lean muscle losses.
Thus, if calorie restriction is severe enough and the initial body fat is low, even exercise will only partially prevent lean muscle loss.(14) It has been found that a moderate energy restriction of .7-1.4% absolute body weight loss per week can retain lean muscle mass.
When subjects underwent a 40% restriction in calories for ten days, despite consuming 2.4g/kg/bw or 1.09 grams per pound of body weight, they still lost lean mass and reduced protein synthesis.(15) In another study, despite subjects consuming 35% of their calories from protein, when subjects consumed a liquid low-calorie diet (<800 calories per day), they still lost muscle.(16)
LOSE FAT WITHOUT LOSING MUSCLE: STUDIES
Studies in athletes have found that during periods of intense exercise and consuming 2 g/kg/bw (close to 1 gram per pound of bw), being in a slight caloric restriction, athletes still had negative nitrogen balance (i.e., breaking down more protein than building).(17)
Pasiakos et al. examined three different levels of protein (0.8 g/kg.bw (RDA), 1.6 g/kg/bw (2X the RDA), and 2.4 g/kg/bw(3 X the RDA). The subjects were placed in a 40% caloric deficit, with 30% from dietary restriction and 10% from exercise.
The portion of lean mass loss was lower, and fat loss was higher in subjects consuming 2X and 3X the RDA compared to the lower protein RDA. There were no differences in the losses in lean mass between the 2X and 3X higher protein groups, but they still lost some lean muscle.
The ratio of lean mass loss to fat mass loss was the following: RDA for protein (58:42), 2X RDA (30:70), and 3x RDA (36:64). The proportion of weight loss due to reductions in fat mass and lean mass was not different between 2X RDA and 3X RDA.(18, 19) If exercise levels are high (i.e., burning 1000 calories per day), increased physical activity results in a decline in the anabolic hormone IGF-I. These response patterns were not altered by dietary protein intake.(20)
SEVERE CALORIES DEFICITS AND MUSCLE LOSS
Thus, severe caloric deficits (>40%) despite high protein can lead to losses in lean mass in various muscle groups. In contrast, moderate decreases in calorie restriction with exercise can completely preserve and/or increase lean mass.(21)
Studies in the military have provided some interesting aspects of severe caloric restriction on lean mass despite having protein supplementation. When a 40% caloric restriction was followed for 21 days, despite the soldiers receiving whey protein (25 grams) resulted in a blunted anabolic signaling response.
Another study found that four 20 g whey protein supplements per day failed to increase whole-body protein retention during a multi-day strenuous winter military training exercise that elicited a severe energy deficit (54% energy deficit).(22) Elite gymnasts who restricted their calories by 400 calories per day and consumed a high-protein diet were able to drop body weight and body fat while maintaining lean mass.(23)
LOSE FAT WITHOUT LOSING MUSCLE: PURE ESSENTIAL AMINO ACIDS (EAAs) SUPPLEMENTATION
When an essential amino acid is missing from the diet, this results in a dampened protein synthesis response. An incomplete protein is missing at least one essential amino acid. If a diet lacks an essential amino acid (i.e., incomplete proteins), foods such as beans, specific nuts, and tofu will not give you all of the amino acids your body needs.
This is why some amino acids are called essential amino acids. Complete proteins contain all the essential amino acids. Amino acids are the building blocks of muscle.
The 9 essential amino acids are histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine. The best essential amino acid supplements should contain all 9 amino acids.
IF A DIET IS LACKING AN ESSENTIAL AMINO ACID
Certain amino acids are called essential amino acids because they are needed for optimal health. When an essential amino acid is lacking from the diet, sub-optimal increases in protein synthesis occur. Plant-based foods and plant-based diets are lower in BCAAs and EAAs compared to meat-based products on a gram-per-gram basis. The BCAAs include leucine, isoleucine, and valine.
Under the normal, non-caloric restriction, ingesting ~20 to 30 g protein or ~10g grams of an essential amino acid complex optimally increases muscle protein synthesis in healthy adults consuming habitual protein intakes of 1.6 g/kg/day during post-resistance exercise.(24) It may be advisable to increase your intake of EAAs through supplementation to preserve lean mass.
In contrast to whole-food proteins and protein supplements, EAAs are absorbed and enter peripheral circulation rapidly, resulting in robust increases in EAA concentrations. High doses of EAA’s supplementation (~24 grams) during a ~30% caloric restriction resulted in greater protein synthesis and less protein breakdown than a control drink of lower EAAs (~8 grams). It was suggested that higher EAAs are needed to offset the catabolic conditions of calorie restriction.(25)
10 grams seems to be the appropriate dose for stimulating muscle protein synthesis; however, larger dosages of EAAs can prevent muscle tissue breakdown when in a caloric deficit. Interestingly, the military is investigating the use of EAAs during soldier operations to prevent lean muscle loss. Since EAAs rather than protein are the drivers of anabolism, the military is looking to maximize protein synthesis with rations rather than focus on total protein.
LOSE FAT WITHOUT LOSING MUSCLE KEY POINTS
- To lose fat without losing muscle, one must increase protein intake and perform resistance exercise.
- Dieting individuals need a higher ratio of EAAs to stimulate muscle protein synthesis than when not dieting.
- Resistance exercise preserves lean mass losses, whereas cardio will not.
- Weekly body weight losses between 0.5-1% have been suggested as optimal; however, this depends on the amount of body fat starting the diet to determine the appropriate deficit.
REFERENCES
5. Eric Russell Helms AM, Andrea Marie Valdez The Muscle and Strength Pyramid: Nutrition. 2019.
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