Think weight loss and the first nutritional compound that comes to the mind is protein. Even among proteins, the debate on whey protein vs. soy protein for weight loss is one that has a lot of people stuck in a dilemma.
Your body is the baggage you must carry through life. The more excess the baggage, the shorter the trip. ~ Arnold H. Glasgow
…. even if that trip happens to be decently long, the burden of carrying all that baggage for a long time is definitely worse than having your trip cut short! No, I don’t mean to say that overweight people don’t deserve to live long – all I want to say is that they deserve to live longer and healthier with a better quality of life. That’s why it becomes imperative to make sure that the body weight is within healthy limits so that all aspects of life can be enjoyed to their utmost extents! Coming back to the issue of protein for weight loss, before we even touch upon the whey protein vs. soy protein debate, let me quickly brief you on what role protein plays in weight loss and fat burning. Proteins, or rather, the amino acids that form the proteins, are the building blocks of the hardware of life. In other words, all tangible aspects of an organism are primarily made of proteins among other organic compounds. Most importantly, the muscle mass is almost entirely made of proteins that take different forms (fibers, connective tissues, etc.) and combine to give the entire musculature its basic architecture.
Now, all of you who are actively involved in weight loss and muscle-building activities are well aware that apart from the bones, blood vessels, glands and other organs in the body, the remaining soft matter is composed of muscles and fats in complementary proportions. That means more muscles leave less room for fats and vice versa. When you workout, you burn fats. Add a high protein intake to your workout regime and there – all that extra vacancy created on burning fats gets occupied by newly developed lean muscles. That leaves even less room for fats to accumulate! It’s like a benign cycle. Also, proteins are very filling. Even if you consume a small amount of protein, you will feel full sooner than, say, if you were consuming carbohydrates or trans fats. Therefore, by eliminating body space for fats and curbing hunger and cravings, dietary protein and supplements help you shed fat and also keep you from gaining weight. Now, coming to the issue of soy protein vs. whey protein in context of weight loss, let’s take a look at the differences so that it becomes easier for you to decide which one’s best for you.
Soy Protein vs. Whey Protein to Lose Weight
Before we enter the ring, let me tell you that the basic difference between these two proteins are the sources from which they are derived. Whey protein comes from dairy sources and is, therefore, an animal protein. Soy protein, on the other hand, is derived from soy beans and is, ergo, a vegetable protein. As for which one’s better for weight loss, check out the following table:-
| Determinant Factor | Determinant Factor Details | Whey Protein Value | Soy Protein Value | And the Winner Is… |
| Biological Value | Proteins are made of amino acids and amino acids contain oxygen, carbon, nitrogen and hydrogen. Carbs and fats have all the above elements except nitrogen. BV is a measure of the amount of nitrogen that is retained by the body on consuming a particular type of protein. Higher percentage of nitrogen retained = better protein digestibility = more protein available for the body to use for repair and fat replacement. | 104 | 74 | Whey Protein |
| Net Protein Utilization | This is the ratio between amount of protein consumed and the quantity of nitrogen emitted by such a protein inside the body. Higher the NPU value, better the utilization of that protein by the body. | 90 | 60 | Whey Protein |
| Amino Acid Score | This factor calculates the amino acid content in proteins from different sources and the quantities are used for comparison with a reference protein for deriving the final score value. The higher the AAS value, more the number of essential amino acids a protein has and the higher its restorative and lean muscle-building capabilities are. | 1.15 | 1 | Whey Protein |
| Total Essential Amino Acids Count | This factor simply takes into account the sum of the quantity of each amino acid that each type of protein contains in totality. The amino acids whose quantities are added for this purpose are Tryptophan, Isoleucine, Threonine, Leucine, Phenylalanine, Valine, Methionine, Histidine and Lysine (total 9 amino acids). | Σ(all 9 amino acids) = 480 mg / 1 g of protein | Σ(all 9 amino acids) = 378 mg / 1 g of protein | Whey Protein |
| Glutamine Content | A non-essential amino acid, glutamine raises the level of growth hormones and this causes the muscles to automatically turn towards fats for getting their fuel instead of blood sugar during workouts and other activities. Higher the glutamine level, better the protein helps muscles to use up fat reserves. | 5 g / 100 g of protein | 11 g / 100 g or protein | Soy Protein |
| Arginine Content | Another non-essential amino acid, arginine helps the body fight fatigue and, therefore, provides more stamina to the body for workouts and tiring exhausting schedule. Hence, more arginine amounts = less fatigue = better ability for rigorous physical training. | 3 g/100g of protein | 89 / 100 g of protein | Soy Protein |
| Protein Digestibility Percentage | This factor is a percentage measure of the amount of protein that is actually absorbed by the body from different sources of dietary and supplement proteins. Higher the percentage, more the protein the body is able to absorb from the source. | 99% | 95% | Whey Protein |
In addition to the table of distinction above, another difference between soy protein and whey protein when it comes to weight loss is that while soy protein is excellent for shedding weight, whey protein helps the body to lose weight and gain muscle mass at the same time due to the higher quantities of essential amino acids present in it. Although the table above may seem somewhat skewed in favor of whey protein, soy protein has its own share of advantages for certain factions of the fitness bandwagon. Being a vegetable protein, soy protein is an ideal nutritional choice for weight loss for vegetarians and vegans. Also, since soy protein has the ability to remove plasma lipids from the body, it is a healthy protein option for individuals who have entered, or are on the threshold of, middle age as it decreases risks of arterial blockage. This also makes it an excellent protein source for people who have a history of cardiovascular diseases.
Soy protein is also extremely beneficial for post menopausal women. However, it should not be taken by individuals who suffer from thyroid problems as soy protein will only worsen the condition owing to its property to mimic certain hormones. Therefore, as far as the verdict for the debate on whey protein vs. soy protein goes, whey protein wins in quantifiable terms. However, in specific areas, soy protein scores over whey protein. It is best to consult your physician and a professional nutritionist regarding which protein would suit you best (based upon your unique individual requirements and health factors) instead of jumping to conclusion in favor of one of these.
