Healthy

Should I eat a high protein diet?

Does having diabetes change your protein needs? Diabetic Living's dietitian and diabetes educator, Dr Kate Marsh, explains.
Young woman eating steak and salad at a benchGetty images

With food companies producing a growing range of high protein foods, from breads and cereals to shakes, powders, balls and bars, you might think we all need to be eating more protein. But are we really lacking in protein? And do you need special ‘high protein’ foods to get enough of this important nutrient?

What does protein do?

Protein is one of the essential macronutrients in our diet (along with fat and carbohydrate) needed for optimal health and functioning of the body. It is a part of every cell in our body and we need it to build and repair tissues and to make enzymes and hormones. Protein is also important for growth and development in children and teens, and during pregnancy. And it plays an important role in building and maintaining muscle mass, which becomes more important as we get older.

How much do we really need?

While it’s an essential part of our diet, we need less than you might think. Australian recommended dietary intakes for adults 19-70 years are 0.84g per kilogram body weight for men and 0.75g per kilogram of body weight for women. This means that a man weighing 90kg would need around 75g of protein and a woman weighing 70kg would need around 53g protein per day. And this isn’t hard to get.

For example, the following would give you more than 80g of protein:

  • Breakfast: ½ cup muesli with 100g Greek yoghurt and berries
  • Lunch: a wholegrain tuna (small can) and salad sandwich
  • Dinner: a chicken (100g) and vegetable stir-fry with rice
  • Snack: a handful of almonds and a regular-size latte (with dairy or soy milk)

If you are watching your weight and blood glucose levels, you may think you should replace carbs with protein. After all, protein doesn’t have the same immediate impact on blood glucose levels that carbs do, and including a little more protein in your diet can help with satiety. But research doesn’t support the benefits of high protein low-carb diets, particularly in the long-term. 

Is a high protein, low-carb diet better?

A 2012 review of 74 studies concluded that while higher-protein diets probably lead to improvements in weight loss and reductions in waist circumference compared to lower-protein diets, the differences are only small and need to be balanced with potential harm. A second (2013) review of 15 long-term studies (at least 12 months) concluded that high protein diets are neither beneficial nor detrimental for weight management, cardiovascular disease and blood glucose management and that there isn’t currently enough evidence to recommend them.

A more recent (2021) systematic review and meta-analysis of 54 randomised controlled trials comparing higher- and lower-protein diets on cardiometabolic risk factors found that higher protein diets resulted in small but positive effects on weight loss, fat mass, systolic blood pressure and some blood fat levels compared to lower-protein diets. However, the researchers conclude that more studies are needed looking at the long-term effects of higher- versus lower-protein diets on diabetes-related outcomes, the incidence of diabetes and cardiovascular disease associated events in high-risk populations (the studies included in the review were in people without a diagnosed chronic health condition).

So what’s the bottom line?

In their 2023 Standards of Care (which are updated annually based on the latest evidence), the American Diabetes Association say that there is no evidence that adjusting protein intake from typical intakes will improve health. Research is inconclusive regarding the ideal amount of dietary protein to optimise either blood glucose management or cardiovascular disease risk. They suggest that protein intake should be individualised based on a person’s current eating patterns. However, they note that there is some research to show that meal plans including slightly higher levels of protein (20–30%) may contribute to increased satiety and help in the management of type 2 diabetes.

Having a bit more protein in your diet can help keep you satisfied and may help with weight management…[but] there is some evidence that eating too much is not good for our health.

How much is too much?

While we need protein, there is some evidence that eating too much isn’t good for our health. In a study of adults aged 50 years and over, the chances of dying from diabetes were significantly higher in those who consumed moderate or high intakes of protein compared to those with lower protein intakes. The same study found that those aged 50-65 years who ate more protein had a 75% increase in overall mortality and were four times more likely to die from cancer. And several studies have now shown that higher intakes of red meat and processed meats, typical of most high-protein diets, are linked with a higher risk of type 2 diabetes, heart disease, bowel cancer and overall mortality. There are also possible negative effects of very high protein intakes on kidney function, particularly in those with underlying kidney disease, which is more common in those with diabetes.

Which groups need more?

Women who are pregnant or breastfeeding and children have higher protein needs. While most of the population is eating enough protein, our national dietary surveys have found that older adults and children are less likely to be meeting their protein needs. Our protein needs increase after we hit 70 due to age-related changes in protein metabolism. Men over 70 need 1.07g, and women 0.94g per kilogram of body weight. Our appetites and energy needs also tend to fall, which means that protein should make up a greater proportion of our total energy intake. Extra protein may help to support good health, promote recovery from illness, and maintain muscle mass and physical function. Although the study found a higher risk of overall and cancer mortality with higher protein intakes in 50-65 year olds, the opposite was seen in older subjects. Higher protein intakes in the older age group reduced mortality risk.

Plant versus animal protein

The risks associated with eating more protein may come down to the source of the protein. Several studies have found that higher intakes of total and animal protein are associated with an increased risk of type 2 diabetes. However, higher plant protein intakes tend to be associated with lower risk. Low-carbohydrate diets based on animal foods have been associated with higher all-cause mortality. Plant-based low-carb diets are associated with a lower risk of mortality. Plant protein has also been shown to be more favourable than animal protein for blood pressure and risk of heart disease. And for those with diabetes-related kidney disease, soy protein has been found to slow the progression of kidney disease compared to animal protein, particularly red meat. However, dairy foods, particularly yoghurt, are associated with a lower risk of type 2 diabetes. 

The take-home message on protein

Having a bit more protein in your diet can help to keep you satisfied and may help with weight management. It is particularly important to get enough as we get older. For most people, protein needs are easy to meet from your usual diet. There is no need to add extra protein from powders, bars or other manufactured ‘high protein’ foods, many of which are highly processed and don’t necessarily provide the other nutrients found in protein-rich whole foods. It is also important to consider where your protein comes from. Avoid processed meats, limit red meat and choose more fish, plant proteins such as legumes, nuts and soy foods, and dairy foods. These foods don’t only provide protein, but also other key nutrients important for good health.

Most foods we eat contain some protein, but the main protein sources in our diet are:

  • Lean meat, poultry, fish and seafood
  • Eggs
  • Dairy foods, including milk, yoghurt and cheese
  • Legumes (lentils and dried beans and peas)
  • Soy foods like tofu, tempeh and soymilk
  • Nuts and seeds
  • Wholegrains, particularly quinoa, buckwheat and amaranth
What foods are high in protein?
  • Lean fillet steak (100g raw) – 22g
  • Chicken breast (100g raw) – 22g
  • Salmon fillet (100g raw) – 21g
  • Firm tofu (150g) – 18g
  • Tuna, small can (95g) – 18g
  • Lentils (1 cup cooked) – 18g
  • Baked beans (220g can) – 11g
  • Chickpeas (1 cup cooked) – 11g
  • 40g (2 slices) cheddar cheese – 10g
  • 1 glass (200ml) low fat milk – 10g
  • Low fat Greek yoghurt (150g) – 11g
  • Quinoa (1 cup cooked) – 7g
  • Boiled egg – 6g
  • Almonds (30g) – 6g
  • Natural muesli (½ cup) – 6g
Protein content of some common foods
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