Whey: the "classic" protein promotes fat loss in the abdominal area.

The classic body is characterized by large muscle bellies accentuated by lean joints and, most importantly, a narrow waistline that is virtually free of belly fat. The routine approach to achieving this classic look involves hardcore training with weights to build muscle, combined with a reduced calorie intake to burn body fat. Low calorie diets can be grueling, especially if the calories consumed do not alleviate hunger and do not adequately replenish the body with nutrients after an intense workout with weights. Reducing food intake also tends to reduce metabolic rate, primarily due to a reduction in muscle mass, which makes it seemingly impossible to build muscle while reducing body fat. However, consuming the right nutrients such as whey protein, which has an amazing capacity to simultaneously reduce hunger, burn fat and stimulate muscle growth even while dieting, should speed up the process of creating the look of a classic body.

Eliminate fat with whey protein

Consuming larger amounts of protein typically promotes a loss of body fat. It is a fact that diets with a daily protein intake of 1.5 grams of protein per kilogram of body weight increase weight loss (1, 2) and body fat loss (2, 3). The consumption of certain types of protein such as whey protein, which are packed with the branched-chain amino acid leucine, has in fact been shown to be even more effective in stimulating fat loss than the consumption of proteins with a lower leucine content. A study conducted by Baer and colleagues that demonstrated this result showed that consuming 56 grams of whey protein per day for 23 weeks generated 5 pounds more fat mass loss compared to another group in the study that consumed an equivalent amount of calories in the form of carbohydrates instead of whey protein. The group consuming the whey protein also lost a full 2.5 inches more in waist circumference than the carbohydrate group, suggesting that much of the fat lost was belly fat.

Burn even more fat with whey protein

A key fat-burning mechanism stimulated by the use of whey protein is food-induced thermogenesis. This process involves the energy cost associated with metabolizing specific nutrients. A commonly used estimate for the thermogenic effect of food is roughly 10 percent of caloric intake, although this percentage can vary substantially depending on the type of macronutrient, with protein intake burning the most calories at about 23 percent, while this value is only 6 percent for carbohydrates and 3 percent for fats (5, 6). The superior thermogenic response to protein consumption relative to carbohydrate and fat consumption makes protein intake the best choice for stimulating thermogenic fat loss.

In addition to consuming more protein to stimulate thermogenic energy expenditure, changing the source of protein may also be an effective way to stimulate additional fat loss, as certain types of protein are more potent stimulators of thermogenesis. In fact, recent studies comparing the thermogenic effects of isocaloric protein-rich meals containing either whey protein, casein or soy protein report that whey protein elicited a much stronger thermogenic response. Whey protein also increased fat oxidation to a greater extent than casein or soy protein (7), making whey protein the clear protein of choice when it comes to reducing body fat.

Lose more fat and keep that fat off by suppressing your appetite with whey protein

Dietary proteins can have a significant impact on body fat levels by suppressing appetite. The appetite suppressing influence of protein consumption can vary based on the unique influence that different types of protein have on certain hormones after consumption. For example, it was recently shown that the production of glucagon-like peptide 1 (GLP-1) - a digestive tract hormone that reduces hunger - increased significantly in response to whey protein consumption, while other proteins such as soy protein had no effect on GLP-1 levels (8). The increased production of GLP-1 is supported by the fact that consumption of whey protein has been shown to reduce hunger more effectively than consumption of soy protein.

The increased GPL-1 concentration from consuming whey protein is likely caused to some extent by the fact that whey protein inhibits the enzyme dipeptidyl peptinase-4, which normally breaks down GLP-1. Thus, the ability of whey protein to inhibit this enzyme ultimately increases GLP-1 levels, thereby prolonging the hunger-reducing effects of this hormone (9). In addition to this, whey protein is supercharged with the amino acid leucine, which has the ability to completely deactivate the energy "measuring" hormone AMPK in the brain. This deactivation of AMPK in the brain directly reduces hunger, which further reduces food intake, resulting in greater fat loss (10).

Maintaining muscle mass while dieting with whey protein

Dieting to lose body fat and not muscle mass seems almost impossible, primarily due to the body's tendency to convert muscle tissue into energy to compensate for the calorie deficit caused by reduced food intake. The consumption of high-quality whey protein can prevent this protein breakdown, especially during a diet. This effect is due to the ability of protein intake to activate the enzyme mTOR, which directly increases levels of muscle protein synthesis while counteracting muscle protein breakdown.

Indeed, a study conducted by Hector and colleagues clearly showed that twice-daily supplementation with 27 grams of whey protein during low-calorie diets increased muscle protein synthesis rates more effectively than 27 grams of soy protein or 25 grams of the carbohydrate maltodextrin. This result shows that a whey protein intake is more effective in maintaining muscle protein and therefore muscle mass during low calorie diets. The authors of the study suggested that the superior effect of whey protein on muscle protein levels observed during this study was most likely caused by the higher leucine content of whey protein, as leucine is the primary driver of mTOR activation, which increases muscle protein synthesis and prevents muscle breakdown, thereby maintaining lean body mass even during dieting.

Whey protein and carnitine do not go together

Carnitine works by transporting fatty acids into the mitochondria, where they are burned to provide energy for the body. Despite the central role that carnitine plays in fatty acid oxidation, carnitine supplementation has been shown to have no effect on fat burning or fat loss when consumed on its own (12). However, a recent study by Wall and colleagues (13) demonstrated a way to increase muscle carnitine levels that actually increase fatty acid oxidation and fat loss. In this study, the researchers gave subjects carnitine while simultaneously administering insulin and glucose. This treatment generated a significant increase in carnitine levels, which stimulated fatty acid oxidation during high-intensity, submaximal exercise. These results suggest that cellular uptake of carnitine is increased when ingested with a glucose-rich meal, which stimulates insulin secretion and transports carnitine into muscle cells.

Since increasing muscle carnitine content represents a tempting intervention for type 2 diabetes and obesity, another study by Shannon and colleagues investigated whether whey protein in combination with a carbohydrate intake could reduce the overall need for carbohydrate to stimulate insulin-mediated carnitine uptake into muscle tissue, since whey protein is rich in leucine, which effectively stimulates insulin secretion. In addition, the ability of whey protein to promote fat loss and increase lean body mass makes whey protein a better choice than carbohydrates for this task, especially for people with type 2 diabetes and obese individuals. Despite these assumptions, the results of this study surprisingly showed that consuming whey protein with a lower amount of carbohydrate completely prevented carnitine uptake rather than increasing it - and this despite an increase in insulin levels that was comparable to the increase in insulin levels in the carbohydrate-only group. The conclusion of this study is that the combined use of protein and carbohydrate to increase carnitine levels for the purpose of fat loss is probably inefficient and therefore cannot be recommended.

References

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