Ask the Doctor: Will more protein help me lose body fat and gain muscle?

When it comes to macronutrients, protein is like the revered hero that can do no wrong. Just on Instagram alone, there are 28.5 million posts with the protein hashtag. The widespread consensus: Eat more protein and you can “lose fat”, “bulk up”, “prevent muscle loss” and “boost metabolism”. It would appear that protein is the panacea to all our weight management woes. However, the truth is more nuanced than that.

Dr Julinda Lee, our resident health advisor, says while all bodies benefit from having adequate protein in our diets, she notes that we may be according too much importance to it. Simply jumping onto the protein bandwagon may find you fatter, derail results, and make you less healthy.

Protein is made up of complex chemical bonds (essentially amino acids strung together in complex formations), hence the body takes longer to break them down. Since it satiates you for longer, you are less inclined to overeat or snack, consume fewer calories, and are more likely to stay on track with a diet. “That’s how it helps with weight management, essentially,” says Dr Lee.

Beyond that, the advantages of beefing up on more protein may be overinflated, especially for sedentary bodies already struggling to manage their weight. We sift fact from fiction:

• Eat more protein to lose body fat

The caveat: Fat loss is still dependent on being in a calorie deficit. As Dr Lee points out: “Proteins have calories. A gram of protein, like a gram of carbohydrate, has four calories, versus fat that has more than double the energy content, at nine calories per gram.”

She reminds us: “Many sources of animal protein come with fat. Hence, trying to increase the protein proportion of your meal may result in an overall increase in calorie consumption, sabotaging weight loss goals.”

In that case, you may be better off eating more carbohydrates if they come from vegetables.

“Vegetables have a relatively low density of calories (meaning a low carbohydrate content per volume) and substituting them for other foods is more likely to result in weight loss,” she explains.

Another thing to note: The body cannot store protein in its original form. Surplus protein gets converted into glucose for energy via a process called gluconeogenesis. The glucose that the body doesn’t need for fuel immediately gets stashed away in our fat stores. Uh-oh.

• Grow muscles by eating protein

Can you really? To grow muscles, you need to progressively overload them (with higher levels of resistance or weights) till they cause micro-tears in your muscle fibres. When the body repairs the damaged fibres by fusing them, this increases the mass and size of the muscles. This is a process called muscle hypertrophy (growth).

Dr Lee confirms this: “Eating more protein will not give you more muscles. You do need to stress your muscles to the point of mild damage, to stimulate muscle cells to hypertrophy and increase in numbers.”

Why do bodybuilding forums keep harping on about protein then?

“Well, you do need to have some protein for post-workout fuelling since it is important for the building of muscles, but it is just as important to reduce post-workout soreness,” she says.

Resistance exercise, she adds, “increases protein retention from the protein that we eat. Since more amino acids are needed to make proteins for muscles, less of it is excreted as urea.”

In short: Protein provides the sustenance for muscle growth, but it’s the workout and rest that makes them grow. A person who does not work out cannot gain muscle simply by eating more protein.

• More protein intake maintains your lean muscle mass

Since having more lean muscle mass keeps bodies metabolically active and makes weight management easier, no surprise that many are eager to maintain muscle mass. One common concern is muscle loss when you lose weight. However, this is an unfounded worry if you’re eating a calorie-appropriate and balanced diet that supports your weight-loss goals.

As Dr Lee assures: “The body tends to burn fat and carbohydrates as preferred sources of fuel (energy). Most weight loss achieved through a calorie deficit will be achieved through the loss of fat as well as water (typically each gram of glycogen is stored with three grams of water), so burning your reserve stores come from fat and glycogen.”

“In endurance athletes who perform at high-intensity levels for prolonged periods of time, protein may form less than five per cent of fuel, hence the importance of proper fuelling during a long period of intense exercise,” she says.

Long leisurely walks or rides along the PCN (Park Connector Network) do not justify an uptake in protein.

While age, genetics, and malnutrition can influence muscle atrophy (the thinning and wasting of muscle), you are more likely to lose lean muscle mass from disuse. Inactivity signals pathways that regulate the process of muscle loss and muscle atrophy in adult tissue occurs when protein degradation rates exceed protein synthesis.

What activates protein synthesis: More exercise, especially resistance training over cardio activity.

• More protein helps the body repair from injury

True, and with less downtime, you will be able to stay consistent with your efforts – this contributes to better weight management. Timing, however, factors into recovery.

Dr Lee points out that even with sufficient protein in your diet, you may suffer from delayed onset muscle soreness (DOMS).

“If you want to fuel for less DOMS and potentially better performance so that you can train on more days with less soreness, then the timing of fuelling is just as important,” she says.

Ideally, within two hours of resistance exercise as suggested by studies, and it’s not all about protein.

She shares: “Taking some protein together with carbohydrates, encourages the movement of amino acids into muscles and this may help to reduce delayed onset muscle soreness, increasing the likelihood that you can attack your next workout with gusto,” she says.

She adds that active recovery is also an important part of improving post-exercise pain. She advises taking an easy walk, doing some light yoga, or swimming on the days when you are sore, post-workout – “this can improve the soreness and aid in quicker recovery.”

• Eat more protein boosts your metabolism

True, you do use up more calories to digest and utilise protein, or what’s known as the thermic effect of food (TEF). Protein has a higher TEF than fat or carbs – 20-35 per cent more compared to five-15 per cent.

Says Dr Lee: “Yes, there appears to be a small discount when eating protein (as compared to other macronutrients) since some calories are lost to protein breakdown products such as urea and ammonia and excreted by the body.”

While some studies have shown that those on a high protein diet can burn through 80-100 calories more per day, consider that 100 calories amount to one large apple or one medium banana. Not a lot if you’re planning on eating your way through more protein just to lose weight. You’re still going to get more burned doing a 30-minute walk at a moderate pace (140 calories).

• More protein optimises gut health

False. We need some of this macronutrient for gut health, but Dr Lee says to think of it like a current account – the body keeps a small store of amino acids to make digestive enzymes. Certain groups of proteins also form the tight junctions between intestinal cells and regulate how permeable the intestinal wall is. However, it does not warrant eating above the recommended protein intake per day to promote good gut health, she says.

The converse is likelier. She warns: “In people who have a poor digestive capability (and typically as we get older, there is less ability for the gastric lining to make acid), and for patients on acid-blocking medications – having too much protein in your diet may increase the likelihood for indigestion, reflux, as well as result in the undigested protein being fermented on by gut bacteria.”

This gives rise to the production of ammonia and hydrogen sulphide (think stinky farts or rotten eggs).

• Eating more protein benefits our hormonal health

The confusion may arise because our hormone receptors require protein, postulates Dr Lee, although she clarifies, “hormones are made largely from cholesterol molecules. Consuming more protein than necessary for health is not likely to benefit it.”

The exception to this may apply to older women above age 65 years, with those in the higher tier of protein consumption appearing to have reduced functional loss. In these studies, she notes, “it did not amount to a very high protein consumption – an average of 90 grams per day – and it is not known if this is a function of just having more protein or if those who ate more protein may have better digestive health or exercise more.”

Maintaining a healthy weight, she agrees, is impactful for hormonal health. Similarly eating a diet that is low in refined sugar and starches, and omega-6-fatty acids (think vegetable oils), and with adequate amounts of omega-3-fatty acids.

“All much more important points to focus on than just protein intake,” she stresses.

She iterates: “Diets that are high in sugars and refined starches, and low in vegetables and other plant foods (nuts and seeds) tend to encourage poor gut health. They increase systematic inflammation, increase insulin resistance, and affect appetite control – all resulting in increased weight, and a great difficulty to shift it if you focus on achieving a calorie deficit alone.”

Too much of a good thing

Let’s be clear, we’re not panning the macronutrient. Protein is critical for our bodies so they can run efficiently and stay healthy. Since we can’t make all the essential amino acids that our bodies need, they must come from varied food sources. Yet a high-protein diet is not the simplistic answer.

Nutritionists like British registered dietitian, Dr Frankie Phillips, are concerned that when people prioritise protein over other foods like whole grains or fruits, we run the risk of being deficient in other important nutrients like fibre that are potentially life-saving.

She notes that in a 2019 study commissioned by the World Health Organisation (WHO) and published in The Lancet medical journal, it was found that most people worldwide currently consume less than 20g of dietary fibre a day. (In Singapore, the recommended fibre intake for women is 20g per day. This amounts to two servings each of fruits and vegetables.)

The same study found that people who eat foods high in fibre and whole grains have a lower risk of heart disease, stroke, diabetes, and other chronic diseases than people whose diets are low in them.

Besides the surplus calories that result from eating more animal protein, Dr Lee also warns of other compounds that are typically associated with meat.

She cites the example of advanced glycation end products in meats that have been charred and cooked on high heat with sugar or carbohydrates, “this can increase the production of free radicals and damage organs in our bodies including the skin (increased photodamage) or the kidneys (kidney failure).”

Cooking protein under high heat can also increase the production of polycyclic aromatic hydrocarbons (PAH), and this can increase the risk of cancer. Proteins from fish can also contain high levels of toxins such as mercury and polychlorinated biphenyls (PCB) and these can increase the risk of many diseases such as hormone dysfunctions and neurological diseases, she warns.

Those with existing kidney disease who continue over-consuming protein may accelerate the progress of their condition, increasing the risk of chronic kidney failure, and require dialysis.

She says that even seemingly healthy individuals, such as bodybuilders who consume large amounts of lean protein and exercise compulsively, risk losing excessive calcium in the urine and may have bone loss as a result. Not what you may expect from a guy with hulking muscles.

How much protein do we need?

Gender, age, and medical conditions influence can influence the amount of protein a person needs, but the one most obvious factor that most people underestimate is how active they are. If you are sedentary, you do not need to eat that much protein. Even if you are active, you don’t need that much more protein either.

There are protein calculators you can use here and here.

Depending on which studies you look at, there might be slight variances in how much protein you should intake. However, the common consensus is that if it’s over two grams per kilogram of your body weight (kgBW), you are consuming too much protein. This applies regardless of age, gender, or activity level.

• For the average sedentary adult (a person who does little or no exercise), you’re looking at 0.8 grams per kgBW to prevent protein deficiency. For an inactive woman who is 75kg, that’s 60g of protein, per day.

• Someone who exercises regularly (30 to 60 active minutes each day) may have slightly higher needs (depending again on the kind of training they do), but it’s still a moderate 1.1 to 1.5 grams for every kgBW.

• People who regularly lift weights, or are training for endurance events (think running or cycling) might need 1.2-1.7 grams per kgBW. Although Dr Lee suggests using 1.35g per kgBW as an upper limit. She notes that although “bodybuilders probably consume way more protein, the specifics of how much protein is needed to build those large muscles are probably beyond the realm of our knowledge.”

For someone who is heavily overweight or morbidly obese though, a more prudent way of calculating it would be to base it on your overall calorie allotment.

Dr Lee recommends that 15 to 20 per cent of your calories come from protein. For example, if you ate 1500 calories per day, 20 per cent of that would be 300 calories; and since a gram of protein is four calories, you would divide that by four to get the grams of protein you need (75 in this case).

Should you cut back on protein as you age?

While it’s true that you need fewer calories as you age, paying more attention to macronutrient counts may elicit better health benefits. One concern for menopausal women is bone health, and sarcopenia (age-related muscle loss). The loss of muscle results in weakness and instability that can affect daily mobility and increase the likelihood of falls.

Here’s where having a little more protein may offer some buffer against muscle atrophy. Dr Lee shares that “some studies suggest increasing protein intake to prevent sarcopenia – between 1-1.2g/kgBW.”

Eating more protein though isn’t the only preventative measure against sarcopenia. The most effective treatment for sarcopenia is exercise.

A study published in 2017, looked at the effect of combined exercise and nutrition intervention on muscle mass and muscle function. It was found that physical exercise had a positive impact on muscle mass and muscle function in healthy subjects aged 65 years and older. In comparison, any interactive effect of dietary supplementation appeared to be limited.

Therefore, more walks, some strength training, aerobics, and weekly swims will still benefit and strengthen maturing bodies.