Protein – How Much do You Really Need?

If one macronutrient is believed to be superior to all others, it’s protein!

We have a huge array of ‘low fat’ and ‘low carb’ diets and food products. We don’t have any diets, food products or supplements that make a point of presenting themselves as ‘low protein’.

How well do you think ‘high carb’, or ‘high fat’ diets, bars and supplements would sell in comparison to their ‘high protein’ equivalents? Not very well I suspect.

Is this because protein really is the super nutrient that we just can’t get enough of, or are there other factors at play?

Do the highly profitable diet and supplement industries unduly shape our perceptions?

Does the fact that our economy relies primarily on the export of dairy and meat result in us viewing protein more favourably than other nutrients?

Or is our general knowledge of all nutrients simply ‘deficient’?

Good nutrition is fundamental to human health. That’s why we cover it in detail in our Personal Training and Weight Management  courses.

Yet in the case of protein, our understanding of this key nutrient is often shaped by those with agendas unrelated to health or athletic performance.

So, in this article, we’ll discuss:

• What protein is and why it’s important
• What the best sources of protein are
• How much the average kiwi needs
• Protein, satiety, and weight loss
• Whether athletes need more protein than non-athletes
• The optimal timing for protein consumption.

What is protein?

Protein, along with carbohydrate (carbs) and fat is a ‘macronutrient’. This means that we need relatively large quantities of it for good health. In comparison, we only need small amounts of micronutrients (vitamins and minerals).

After water, protein is the most abundant chemical compound in the body. Every cell, tissue and organ in our body is made up of protein. There are at least 10,000 different proteins that make you and I what we are and keep us this way.

At a structural level, proteins are made up (synthesised) from a combination of 20 different building blocks known as amino acids.

Amino acids are classified as either essential or non-essential.

This classification is misleading as all the amino acids are in fact ‘essential’. In the context of amino acids, ‘essential’ means that they need to be consumed in the diet. Non-essential means they can be synthesised within the body.

Sometimes this classification system goes a step further to classify amino acids as ‘conditionally essential’. For example, histidine is considered non-essential for adults but essential for infants who are unable to synthesise it effectively.

Why is protein important?

During the process of digestion, protein foods are broken down into their amino acid building blocks. They are then re-synthesised into new proteins which serve a variety of important roles in our growth, development, and everyday functioning.

Amongst other things, proteins:

• Provide structure – forming the skeleton, muscles, skin, and connective tissue
• Enable muscle contraction via the proteins actin and myosin
• Form antibodies which assist the immune system to fight infections
• Transport oxygen around the body via the protein haemoglobin
• Co-ordinate bodily functions. For example, insulin, a protein hormone, regulates our blood sugar
• Facilitate biochemical reactions via enzymes such as pepsin which aids digestion.

Protein is vitally important because these functions are essential not only to well-being, but to life itself.

In fitness, we tend to view protein favourably because of its role in muscle contraction and the growth of muscle tissue. There’s an underlying logic for ourselves and our clients – the more we consume, the more lean muscle we’ll develop.

Unfortunately, this logic doesn’t translate into reality.

Once the body has fulfilled its needs, excess protein is either:

• Converted into glucose or ketone bodies and used for energy
• Converted into fatty acids and stored as body fat.

Generally, protein will only be used as a source of energy when energy from other macronutrients (carbs and fat) is deficient. In New Zealand, this is seldom the case.

Therefore, the excess consumption of protein is most likely to result in the accumulation of body fat, rather than the accumulation of additional muscle tissue.

What are the best sources of protein?

It’s important to understand that protein isn’t a food per se. Rather, it’s a nutrient found in many different plant and animal foods.

Proteins are often described as complete or incomplete. Complete protein foods contain all the amino acids required by the body to synthesise new proteins. In contrast, incomplete protein foods lack one or more of the essential amino acids.

Animal-based foods tend to be good sources of complete protein while plant-based foods are often ‘incomplete’.

Being ‘incomplete’ doesn’t necessarily mean the food source is inferior. It simply means that a greater variety of protein rich foods need to be consumed. Vegetarians and vegans can satisfy their protein requirements via a plant-based diet – they just need to ensure that their diet includes a rich variety of plant foods.

The following table details some common food sources and the amount of protein and energy they provide:

It’s worth noting that when protein rich foods are consumed, multiple other nutrients are also consumed. While red meat is a good source of protein it’s also high in saturated fat which is strongly associated with cardiovascular disease (CVD). Also associated with CVD is a high intake of sodium (salt) which is common in processed meats (salami, bacon, sausages) and takeaways.

And in terms of environmental impact, the production of animal-based foods tends to have far higher green-house-gas (GHG) emissions than plant-based foods. The production of red meat stands out for it’s disproportionately negative impact on emissions.

In New Zealand, agriculture is our biggest emitter of GHG. And run-off from industrial beef and dairy farming in particular, has contributed to many of our lakes and rivers becoming unsafe to swim in, or drink from.

When choosing the best sources of protein to consume, there’s a lot to consider!

How much does the average kiwi need?

Recommended dietary intakes (RDIs) for protein are often expressed in grams per day (g/day), or grams per kilogram of bodyweight (g/kg). For adults, the Ministry of Health (MoH) recommends the following:

*NB – the data in this table is based on the ‘reference’ adult who weighs 76kg (male) and 62kg (female). The average New Zealand adult is considerably heavier than this.

Because the g/day formula is somewhat tricky to follow, the MoH has moved away from RDIs. New Zealand’s Eating and Activity Guidelines (for adults) now recommend people consume a certain number of serves per day.

With regard to foods containing protein this translates to:

You’ll note that for most people this is much easier to follow.

There are some major points of interest with regard to these serves per day, namely:

• The higher serves of milk and milk products for females and older adults relates principally to the mineral calcium (for bone strength) rather than protein
• Recommended serving sizes are normally significantly smaller than most people’s actual serving sizes
• The MoH guidelines allow between 2-3 extra daily servings of protein foods for large people and/or physically active people.

Because the New Zealand diet is typically high in animal products we generally don’t lack for protein.

The MoH raises a major area of concern with regard to our increasing consumption of processed and takeaway foods. When processed, foods often lose essential nutrients or have extra substances added which are often not beneficial to health.

For example, processed meats like salami, sausages and luncheon often have extra fat added to them along with preservatives and food additives to improve their taste and shelf-life. When processed, bread may still provide protein, but the dietary fibre is removed reducing the nutritional quality of the product.

Do athletes need more protein than non-athletes?

Awhile ago I studied a paper in Sports Medicine under the tutelage of Dr Dave Gerard. ‘Dr Dave’ was:

• Doctor for New Zealand’s Olympic and Commonwealth Games teams in the 1980s-1990s
• ‘Chef de Mission’ (person in charge) of the New Zealand team at the 1996 Atlanta Olympics.

I remember him talking about the ‘urine’ at Olympic and Commonwealth Games being ‘the most expensive in the world’! His explanation was that regardless of actual need, athletes take every supplement they can if they think it might offer the slightest chance of performance improvement.

In reality though, excessive supplement use simply translates into expensive waste products!

We seem to approach protein consumption in a similar way.

Sports nutritionists Moore et al. [ref 1] note that athletes do need more protein than non-athletes. After all, training, especially intense training, increases the breakdown of skeletal muscle which requires a greater intake of protein to rebuild.

These nutritionists observe that:

• A protein intake of 1.2 – 1.7 g/kg/day meets the needs of most strength and endurance athletes
• This increased requirement is usually achieved by increasing general food intake
• Excessively high protein intakes risk displacing other important nutrients such as carbohydrates – remedied by encouraging the regular consumption of fruit and vegetables.

It’s worth noting that New Zealand’s general consumption of animal foods is so high that international commentators have observed:

• That if the rest of the world ate like us, we’d need another planet to sustain us all!

So yes, athletes do need more protein than non-athletes. But in New Zealand it’s likely that our current diets are more than adequately meeting this increased need.

What’s the optimal timing for protein consumption?

Moore et al. [ref 1] note that the consumption of large quantities of protein at any given time merely stimulates protein oxidation (the breakdown of consumed protein). It doesn’t necessarily enhance the synthesis of new protein and the building of new muscle tissue.

As such, these sports nutritionists recommend focusing more on consuming smaller protein-rich meals throughout the day, rather than on total protein intake. They argue that such a focus is more likely to result in enhanced physiological adaptations.

They provide an example of a balanced daily dietary intake for an athlete below:

Because training (especially intense training) can increase protein metabolism for up to 48 hours post-session, such a dietary intake needs to be followed throughout the week. Not just on training days.

In our increasingly time-poor world, following such a plan and consuming regular meals can be a challenge. This is one area where supplementation may be beneficial. Protein shakes can provide a quick, easily consumable means to achieve a balanced nutrient intake throughout the day.

Moore et al also note that such shakes don’t need to be the expensive, shop bought powders. They can be homemade; adding skim milk powder and fruit to water (or milk) can provide a cost-effective means to fortify a shake with carbs for energy, and protein for muscle growth and repair.

Protein and weight loss – does it really increase satiety?

Protein also receives lots of positive press because of its supposed ‘satiating’ effect. Satiety refers to the feeling of fullness we get after eating. Scientific, and popular literature is full of articles claiming that high protein diets increase satiation.

By this mechanism, protein is advanced as the superior macronutrient in our fight against obesity. The logic goes that the fuller a person feels the less they’ll eat, and the fewer calories they’ll consume.

For example, in a review of studies investigating protein and satiety, a Spanish study [ref 2] concluded that:

“Protein is the most effective food macronutrient providing a satiating effect. Thus, formulating foods with increased protein content can help to modulate food intake, promoting body weight loss and body weight maintenance thereafter”.

Hopefully these conclusions weren’t influenced by:

• Spain being a significant exporter of pig meat, and
• The ‘Spanish Ministry of the Economy and Competitiveness’ funding the study.

It always pays to look at who’s funding the research to consider whether ulterior motives might be at play.

Additionally, a problem with making such absolute conclusions is that they’re not supported by a significant body of research. The influence of protein on satiety is a contentious area.

For example, Lim et al [ref 3] recently completed an eight-week study on 121 women with obesity. The women consumed a fixed, low-calorie diet and were randomly assigned to either a:

• High protein group (consumed 1.2g/kg/day) or a
• Normal protein group (consumed 0.8g/kg/day).

These diet groups were combined with either a:

• Normal carbohydrate intake (40% of daily energy intake) or a
• Lower carbohydrate intake (28% of daily energy intake).

The study found that:

• In comparison to a normal protein intake, a higher intake did not promote satiety and bodyweight loss, irrespective of carbohydrate intake.

The jury is out regarding protein’s impact on satiety and is likely to remain so.

Let me explain,

In our Weight Management programme we take an in-depth view of satiety.

It turns out that we don’t have a very good system for measuring satiation because overeating hasn’t been an issue throughout human evolution.

Food shortage has characterised the majority of our history. As such we needed a digestive system that allowed us to take full advantage of limited food resources when they were available. In short, we needed a digestive system that enabled us to overeat and that’s exactly what we have.

Our stomach is made of smooth, elastic muscle that stretches to accommodate a large volume of food. By the time the stretch receptors in our stomach let us know that our stomach is full, it’s likely that we’ve already consumed far more than we actually need.

The reality is – satiety is not a particularly effective means of limiting caloric intake and promoting weight loss.

However, consuming unprocessed food in its most natural form slows the digestive process. The longer food is in the stomach then the longer it takes for us to feel hungry again. So, in a way, protein does have an influence on satiety, although this influence applies to unprocessed food in general.

The Final Word

Protein, like all macro and micronutrients is essential for good health and athletic performance. However, we do tend to over-rate it’s value relative to other nutrients. In part, this can be attributed to the influence of vested interests – the diet and supplement industries and our economic reliance on animal foods as a country.

In reality, the typical kiwi diet, high in animal foods, provides more than enough protein for the general and athletic populations. This doesn’t mean that there isn’t room for improvement.

For better health and performance, we can:

• Focus on consuming healthier sources (unprocessed cereal and animal products)
• Reduce our intake of ultra-processed foods
• Spread our intake over the day (have smaller, more frequent meals)

References

1. Moore et al. (2017). Chapter 4: Protein. In Burke & Deakin. (Eds). Clinical Sports Nutrition (5th Edition). Australia: McGraw Hill Education
2. Morell & Fiszman. (2017). Revisiting the role of protein-induced satiation and satiety. Food Hydrocolloids. https://doi.org/10.1016/j.foodhyd.2016.08.003
3. Lim et al. (2022). Does a higher protein diet promote satiety and weight loss independent of carbohydrate content? an 8-week low-energy diet (LED) intervention. Nutrients. https://doi.org/10.3390/nu14030538