Protein powder is more popular now than it has ever been, with a surprisingly large increase in sales to women. Even just a few years ago, the popular perception of protein powder was that it was something that only bodybuilders or athletes would use.
But thanks to clever marketing from supplement campaigns, and a large switch in public opinion/knowledge about women lifting heavy weights, protein powder is now a common supplement for women.
While younger women may feel no stigma in taking a traditionally “male” supplement, older women may be less likely to start taking it. This is a problem, because the older you are, the more protein you need.
A 2012 study on elderly men found that as you age the anabolic response to protein ingestion is reduced, meaning that elderly men and women require more protein than younger men and women to build and maintain muscle (though not all studies agree on this) (1).
1Increased protein intake can increase muscle growth. One of the most well documented benefits of protein is its effect on muscle growth. Exercising without sufficient protein intake will lead to poor muscle growth, and potentially muscle loss. But if you increase your protein intake to match, you will create a positive muscle protein balance which will lead to muscle growth (2).
It is partly for this reason that athletes require more protein than regular (non-athletic) people. A study in 2016 found that strength athletes require significantly more protein as sedentary people do, 1.5 to 2 times more (3).
This is partly due to the need for increased muscle mass, but also for recovery. Female athletes (even amateur ones) need to fully recover from gym sessions, or sporting events.
2Protein powder can help reduce body fat. A study in 2015 found that a combination of whey protein and resistance exercise was more effective at reducing body fat than taking carbohydrates alone after exercise (4).
The study also found that whey protein post-workout helped people to maintain fat free mass (muscle) better than taking carbohydrates alone. In fact, the protection of fat free mass during a diet is one of protein powders’ most important benefits.
A calorie deficit diet is the primary way to lose weight, whether you create that deficit through diet alone, increased exercise, or a combination of the two (recommended). As the energy balance becomes negative the body uses stored energy (adipose tissue – or body fat as we know it) to keep our metabolism in order. This leads to a reduction in adipose tissue and a leaner body.
Sadly it’s not as easy as that. If you’ve ever looked at people who have been starved they don’t tend to look incredibly ripped with amazing abs. This is because a prolonged calorie deficit doesn’t just reduce body fat, but it can also reduce muscle mass.
Whatever your thoughts on women with muscles, losing muscle mass during a diet is not the solution. It is unpleasant, the body suffers, and your metabolism will be reduced.
3Protein can help to improve recovery. Poor recovery can cause a lot of issues for anyone training at a high intensity, and proper protein intake is a large part of that. A 2018 study found that combining protein with carbohydrate post-workout can accelerate recovery especially in individuals following a low-carbohydrate diet and who wish to repeat exercise without extended recovery time of several days (5).
4Keeping protein levels high can help to prevent the loss of muscle mass during a diet. Or more specifically it can limit any muscle loss to the smallest amount possible (if you are on a prolonged diet you’ll still lose a small amount of muscle mass).
A study in 2013 found that consuming double your protein intake (just like the athletes in the 2016 study above – reference #3) could protect muscle mass during short-term weight loss diets (6).
Another benefit of taking protein powder while on a diet is the high protein to calorie ratio. When you are trying to keep protein high but your calorie targets are low, food choices become important. Peanut butter is technically high in protein, but the ratio of protein to calories is very low.
100g of peanut butter will provide 25g of protein, but is 588 calories. Compare that to a protein shake which can also contain 25g of protein but is only 114 calories (for example).
5Whey protein (and other protein powders) is effective at increasing satiety – this refers to how full you feel after a meal. This is perfect for weight loss diets as it may prevent overeating or snacking between meals. It can also supplement lower calorie meals.
One study found that whey protein reduced short term food intake compared to a placebo group, and compared to carbohydrates (7). A 2013 study found that pea protein and casein protein resulted in even higher satiety and reduced food intake compared to whey when ingested 30 minutes before the meal (8).
Researchers attribute this satiety effect to several factors:
- amino acids that are released after protein is digested increases release of satiety hormones
- protein (and fat) slows down gastric-emptying, increasing satiety because food remains in the stomach longer
- whey and other protein sources reduce post-meal blood sugar response compared to higher carb meals (9) due to increased insulin levels and enhanced insulin sensitivity despite low carb intake.
6Protein may help improve metabolic health. According to McGregor & Poppitt (2013) milk protein (whey or casein) has been linked with improved metabolic health, and a reduction in the chances of type 2 diabetes (10).
The study claims that this stems from both direct and indirect benefits of dairy protein.
So just as we mentioned above, the increase in fat loss through raised satiety, increased muscle mass, and protection of muscle mass during a diet all indirectly reduce the risk of type 2 diabetes. This study also reports that a variety of milk proteins, both fermented and unfermented, lowers blood pressure, a risk factor for hypertension and metabolic disease.
7Protein powder can elevate protein synthesis. Taking protein in the 4-6 hours after a workout will elevate protein synthesis helping the body to begin the process of repair and re-growth of damaged muscle fibers (11).
But protein powder is not just beneficial for women who train for strength or hypertrophy. In fact it is rarely marketed as such. Protein powder has been shown to be effective at promoting fat loss as well.
8Protein powder increases overall protein intake. You could get the same benefits from a high protein diet without whey protein (or casein, pea, soy, or hemp). The simple fact is that without protein powder, many people struggle to get anywhere near their protein requirements when their needs are increased due to exercise, survey, illness or disease, especially when aiming to control calories.
A 2010 study by Wright & Wang found that the average protein intake for men was 15.9% while women only managed 15.5% (12).
Another study in 2008 found that many Americans consume below the recommended intake (which may be too low of a target based on individual health, goals, exercise and disease) (13).
Protein powder is a convenient way to meet protein needs: it is easy to transport, easy to store, comes in a variety of flavors, is adaptable to different recipes, and can be prepared in seconds.
9Soy Protein powder can reduce oxidative stress. It’s not just whey protein that is effective though, other proteins such as soy can also have benefits. A study in 2004 by Brown, DiSilvestro, Babaknia, & Devor compared whey protein, soy protein, and no protein intake after exercise (14).
It found that soy protein powder, but not whey, was effective at preserving anti-oxidant function after exercise. This means that taking soy protein powder after a workout can reduce oxidant stress, which occurs during intense workouts (15).
That being said, in a couple of studies where they compared whey protein and soy protein, the researchers found that whey protein was more effective than soy protein at increasing weight loss. The first study was published in 2011 and was performed on overweight and obese adults over 23 weeks.
It found no change in body composition in the soy protein group but the whey protein group had lost between 1.8 and 2.3kg (16).
The second study was performed on both young men and young women (18 female, 9 male) (17). It found that when using larger amounts of both whey and soy protein powder led to similar results muscle growth.
While on the subject of milk based protein powders, a 2007 study found that milk based protein supplementation can help to increase bone mineral density in young women (18).
1Protein powder may cause bloating. There has been some evidence of bloating, but this is usually related to lactose intolerance or milk protein intolerance. In fact, there is ample research that document there being absolutely no bloating, diarrhea, or nausea in any of the subjects.
For example, this study on 33 young women found no evidence of bloating, nausea, or diarrhea in any of the subjects over a 6 month period of taking milk based protein powder (19).
2Protein powder may increase insulin resistance – This is by no means a certainty, but at least two studies have found whey protein may lead to insulin resistance (a leading cause of type 2 diabetes). One study was performed in 2002 and found that “plasma amino acid elevation induces skeletal muscle insulin resistance in humans” (18). Other studies have confirmed this finding (20).
Other studies contradict these findings as mentioned above in the metabolic health benefit section.
3Protein powder may increase mortality – A 2014 study found that people on low protein diets (aged 50 to 65) were more likely to live longer and less likely to get cancer (21). These negative effects were minimized when plant protein was the primary protein source. The study also showed that a higher protein intake in the elderly (>65 years old) actually improved their lifespan and reduced the risk of cancer.
Other studies have demonstrated that whey protein stimulates mTOR and IGF-1, which when chronically stimulated (without exercise stimuli) can result in reduced life span (22).
As we have said before, age, exercise level and health goal influences how much and of what kind of protein the body needs.
4Protein powder can be stressful for the kidneys – For years one of the most common myths about protein powders was that too much was bad for your kidneys. There is even some evidence to support this, a 2011 study (on rats) found that a high protein diet caused alterations in renal health (23).
But even this study found that resistance exercise provided a protective effect. The research appears to support the combination of exercise with an increased intake of protein to minimize high protein diet risks.
In 2011 the World Health Organisation (WHO) stated that renal failure is not due to high protein diets, but is in fact a natural side effect of the decline in protein intake as you get older (24).
In people with healthy renal systems a high protein diet is perfectly safe, and may even be beneficial. However, if you already have a kidney disease then you should avoid a high protein (or even medium protein) diet per the WHO and other experts (25).
5Protein powder can have an effect on pregnancy – A study on mice found that a high protein diet led to smaller birth weight than a low protein/high carbohydrate diet (26).
But, considering that whey is found in cheese and milk and these are two very commonly consumed products by millions of pregnant women, whey itself is unlikely to be an issue. The complications arise from excessive protein intake.
The truth is that protein powders carry little risk with the potential for many benefits. If you have a milk protein allergy or lactose intolerance then you can expect unwanted side effects. Swapping to soy, rice pea or hemp protein powder instead would be a safer choice.
There has been no causal link found between a high protein and mortality, and considering the hundreds of benefits that protein has it seems unlikely that we will find one.
6Protein powder may worsen bone health in women. The World Health Organization states that the balance of protein and potassium intake influences bone health in women due to the balance of acidic and alkaline substances in the body. They report that a lower intake of protein combined with a high intake of potassium present in fruits and vegetables led to better measures of bone health in women (27). This has been supported in bone health studies that found improved bone mineral density in women following vegetarian and plant-heavy diets (28).
7Protein powder, when part of a high protein diet, may result in too little fiber intake. Animal-based sources of protein contribute no fiber which can make it more difficult to reach fiber goals when following a high-protein, animal-based diet. The average American already consumes less than 18 grams of fiber per day, far below the recommended intake of 25 grams a day for women and 38 grams a day for men. This can jeopardize long-term health by not providing enough fibrous material to nourish gut bacteria, improve digestion, control cholesterol and enhance satiety.
Dosages vary based on individual needs: A max of 1-2 servings per day is recommended for the general population.
A study in 2013 looked at recommended daily amounts of protein for elderly people, they found that between 1 to 1.2g of protein per kg of body weight was sufficient per day for people aged over 65 (29). This equates to 95 grams of total daily protein needed for a 175-pound person.
But the study also found that elderly people who were suffering with severe chronic diseases require even more protein, perhaps up to 1.5g per kg.
On the other end of the spectrum, a study by Helms, Aragon, & Fitschen published in 2014 looked at natural bodybuilders. The study found that the optimal level of protein intake for a natural bodybuilder would be between 2.3-3.1g of protein per kg of lean body mass, not total body weight (slightly different to the above study which used bodyweight) (30).
Now most women are not natural bodybuilders, though it is becoming more and more common.
Sedentary individuals should aim for 0.8g of protein per kg, while active people should hit 1-1.5g per kg. Highly active people and bodybuilders people should aim for between 1.5 and 2g per kg (31, 32).
As you can see, a lot of well respected sources provide different recommended dosages based on many variables. A summary has been provided below compiling much of the above data (these goals may still change based on individual needs and goals):
- Inactive, <45 years of age – low to moderate protein intake, 0.8-1.2g/kg BW
- Active, <45 years of age – 1.2-1.5g/kg BW
- Middle-aged, Inactive – 0.8-1.0g/kg BW
- Elderly (>65 years old) – 1.0-1.2g/kg BW (increase with illness or injury)
- Illness, Post-surgery – 1.5+g/kg BW
- Bodybuilders, Athletes – 1.5-2g/kg BW
Now we have an idea of how much protein you can have per day, we should look specifically at protein powders. A study in 2013 found that a serving of 20g of whey protein was sufficient for maximal stimulation of protein synthesis in younger people (33).
In contrast, a study on the elderly found that instead of 20g, a serving of 35g of whey protein was required for maximal stimulation of protein synthesis (34).
The reason for this is due to the anabolic response to protein ingestion is reduced in the elderly. Studies have shown that older people require more leucine, an amino acid which whey protein is high in (35).
So if you are a 70kg (154 lbs) 30 year old, active woman your protein requirements would be a max of 1.5g per kg or 105g per day. Of that 105g, a large percentage should come from foods rather than supplements. Protein-rich foods include meat, dairy, legumes, soy and fish.
You could consider taking a protein shake in the morning alongside breakfast or post-workout, and a casein protein shake before bed. Studies have shown casein to be more effective than whey when taken before sleep for muscle growth (36).
Is protein good for weight loss? Replacing regular meals with protein shakes or higher-protein meals may help you reduce your daily calories and enhance satiety, which may help you lose weight.
How much protein should women get per day? The US Department of Agriculture recommends that all men and women over the age of 19 should get at least 0.8 grams of protein per kilogram of body weight per day (or 0.37 grams per pound). That means a woman who is 130 pounds should get at least 48 grams of protein.
Is whey or casein better? Neither is better as they both serve different purposes. Whey protein is best post workout to promote recovery. Casein is best as a meal replacement or before bed since it’s more filling and slowly releases protein into the blood stream.
Do protein shakes cause weight gain? Weight gain occurs when you eat more calories than you burn. If your daily protein shake contains 200 calories in excess of your body needs, it could result in a gain of 21 pounds in a year.
Do protein shakes make you fart? Sometimes protein can cause intestinal distress leading to protein farts. Taking a probiotic or a high quality protein powder should remedy this. You may need to switch to a different type of protein if it persists.
Protein powder is an excellent tool for any woman, whether they are young or old, overweight or underweight, active or sedentary.
Protein powder is safe to use, easy to transport, adaptable to different meals and snacks, and quickly absorbed. While a healthy, plant-heavy diet is recommended as the basis for nutrition, protein powder may help increase muscle strength and fat loss benefits, reduce risk of metabolic diseases, and improve overall health by helping you meet your individual protein needs.