Increasing dietary protein may reduce weight gain as women approach menopause

Menopause refers to the point in time when a woman has not had a menstrual period for 12 months. The average age at which menopause occurs is 51 years, according to the Australasian Menopause Society, and most women will have symptoms for five to ten years prior. Weight gain during the transition to menopause, a phase referred to as perimenopause, is a well-recognised feature. Yet little is known about the underlying causes of progressive weight gain during perimenopause.

Researchers from the University of Sydney’s Charles Perkins Centre, led by Professors Stephen Simpson and Arthur Conigrave, are starting to shed light on this. In one of their recent studies, published in the September 2022 issue of BJOG, the researchers show that a slight increase in the daily intake of protein may help minimise weight gain during perimenopause.

In the study, the researchers sought to determine whether a concept – known as the protein leverage hypothesis – could explain the weight gain during perimenopause that affects many women.

The protein leverage hypothesis predicts that humans prioritise protein when regulating food intake. As a result of this strong appetite for protein, compared with the other two macronutrients – carbohydrates and fats, humans will adjust their food intake to achieve a relatively constant level of dietary protein. This priority to satisfy protein intake within narrow boundaries can result in overconsumption of energy, particularly when dietary protein is diluted by fat and carbohydrates – a common feature of highly processed foods.

The researchers created models using previously published perimenopausal data, demonstrating the shift in protein intake and energy required to minimise weight gain during perimenopause.

Why would perimenopausal women need more protein?

During perimenopause, hormone changes – such as reducing oestrogen levels – increase the rate at which protein is broken down in the body. This increased breakdown of protein acts as a trigger, signalling the body to replenish protein to its optimal level.

Failing to meet the body’s appetite for protein can lead to overconsumption of other energy sources, such as fat and carbohydrates. This excess consumption of fat and carbohydrates can result in weight gain and obesity. This increases the risk of cardiometabolic diseases, such as heart attack, stroke, diabetes, insulin resistance, and non-alcoholic fatty liver disease.

Why would we consume more fat and carbohydrate if our body craves more protein?

The body has a specific appetite for protein which drives the regulation of protein – aiming for a target range of 15-25% of the total daily energy. If protein is low, the body sends signals to the brain to stimulate protein appetite. This appetite for protein is maintained until the target range has been achieved.

Replenishing protein can be relatively easy if the source is from whole foods. However, with the abundance of highly processed foods generally low in protein and high in fat and carbohydrate, it can be easy to overconsume as the body tries to meet its daily protein needs.

Armed with this new knowledge, what are the researchers recommending?

The researchers indicate that relatively minor adjustments, as little as a 1-3% increase in the daily dietary protein intake, could reduce and even prevent weight gain during perimenopause. The level of adjustment is also influenced by changes in physical activity – with a decrease in physical activity during perimenopause requiring a slightly higher daily dietary protein intake.

What does a 1-3% increase in daily dietary protein intake look like?

Lou Edney, nutritionist and founder of Nourishing Nosh, says the study ‘provides health professionals with solid evidence and motivation for people to increase their protein consumption during perimenopause, and more importantly, to ensure adequate intake of protein in the first place.’

‘It’s a little tricky to translate this research into simple advice that suits everyone because there is so much variance in energy and protein needs between individuals.’

‘For simplicity, we will illustrate with an example of a woman with a total daily energy intake of 8000 kilojoules (kJ) who is eating the right amount of protein for them – 16% is the minimum recommendation and the figure used in the research.

• 16% protein energy = 1280 kJ (= 77 g pure protein per day).

• Increase by 1% to 17% protein energy = 1360 kJ (= 80 kJ protein or an additional 4.8 g pure protein per day).

• Increase by 3% to 19% protein energy = 1520 kJ (= 240 kJ protein or an additional 14 g pure protein per day).’

‘If your diet is already balanced and full of fresh vegetables and fruit, lean protein and high-quality fats, the easiest way to increase your protein (without increasing your energy intake) is to substitute a lower protein food in a food group for a higher protein food in the same food group’, says Edney.

For example, Edney suggests the following swaps:

• Two-thirds of a cup of cooked cannellini beans (6.2 g protein) for the same amount of cooked black beans (8.9 g protein). That’s an increase of 2.7 g of protein. Or 80 g wild sardines (18 g protein) which is an increase of 11.8 g protein.

• One cup of rice milk (1 g protein) for the same amount of oat milk (2-5 g protein).

• Thirty grams (¼ cup) of macadamia nuts (2 g protein) for the same amount of hemp seeds (10 g protein) for a net gain of 8 g protein.

‘Another strategy could be to spring clean your diet and remove energy-dense but nutrient-poor foods with higher quality protein options. For example, replace ½ cup white rice (494 kJ, 2 g protein) with an egg (60 g = 383 kJ, 6 g protein).’

As daily energy requirements are unique to each person, the findings of this study should be discussed with a qualified nutritionist, dietician, or appropriate healthcare professional before any significant changes to your diet are made.

Want to know more about menopause?

According to the Australasian Menopause Society, all women are affected by menopause in some way. For most women, menopause occurs between the ages of 45 and 55 and is defined by a lack of a menstrual period for 12 months. Hormonal changes such as reduced oestrogen levels are responsible for symptoms during the transition to menopause, with many women having symptoms for five to ten years before menopause occurs. If you have any questions about menopause or the transition to menopause, talk to your doctor or a qualified health professional.

You can find further information and resources on menopause and the transition to menopause at:

• Australasian Menopause Society: menopause.org.au

• Jean Hailes for Women’s Health: jeanhailes.org.au