If you've reached your 40's or 50's and feel that your body doesn't respond to food in quite the same way it used to, you're certainly not alone!
Many of the women I work with tell me that once they find themselves wandering the twilight zone of midlife (aka their ‘why does my knee hurt when it rains’ era), their body doesn’t seem to respond to food in quite the same way it used to. They haven’t dramatically changed the way they eat, yet they’re finding it harder to maintain muscle, manage their weight or recover from exercise.
While there are many reasons for these changes, one macro nutrient becomes increasingly important as we age – protein.
Protein in midlife becomes non-negioable. It’s always been important, but the difference is that, as we age, our bodies become less efficient at using it. At the same time, the consequences of not eating enough protein become more noticeable.
Protein is about much more than muscles
When people think about protein, they often picture bodybuilders, protein shakes or athletes trying to build muscle. In reality, protein is involved in almost every system in the body.
It provides the building blocks for muscles, bones, skin and connective tissue. It is needed to make enzymes, hormones and antibodies, helping to support everything from immunity to wound healing. Protein also plays an important role in regulating appetite and maintaining more stable blood sugar levels. Meals that contain adequate protein tend to be more satisfying, helping us feel fuller for longer and making it easier to avoid reaching for snacks a couple of hours later.
So while maintaining muscle is one of protein’s most important jobs, it is certainly not its only one.
Why does protein become more important in midlife?
From around our forties onwards, several changes begin to occur. Muscle mass gradually declines, a process known as sarcopenia. This happens naturally with ageing, but hormonal changes, reduced activity levels and periods of illness can all accelerate the process. At the same time, our muscles become less responsive to the protein we eat. Scientists call this anabolic resistance.
In simple terms, this means it takes a little more protein, combined with regular resistance exercise, to achieve the same muscle-building and muscle-maintaining effect that came more easily in our younger years. The result is that preserving muscle requires a little more attention than it once did.
Why muscle matters, even if you're not trying to build it
Many people assume that muscle is mainly about strength or appearance. In fact, muscle is one of the most metabolically active tissues in the body. It helps regulate blood glucose by acting as one of the body’s main storage sites for glucose after meals. It supports balance and mobility, reducing the risk of falls as we get older. It helps maintain bone strength by placing healthy stress on the skeleton, and it enables us to remain active and independent throughout later life.
Muscle also contributes to our resting metabolic rate. While it’s unlikely to transform calorie burn on its own, maintaining muscle makes it easier to stay physically active, recover from exercise and support a healthy body composition over time.
Why many women struggle to eat enough protein
One of the first things I look at when analysing a food diary is how protein is distributed throughout the day. It’s very common for women to tell me they think they’re eating plenty of protein, but when we calculate it together, they’re often only reaching 40 to 60 grams a day. A typical day might include cereal or toast for breakfast, soup or a sandwich for lunch and then most of the day’s protein arriving with the evening meal. By that point, it’s difficult to make up the shortfall.
Our muscles respond best when they receive protein regularly throughout the day, rather than almost all at once in the evening.
How much protein do women need (and how it changes in midlife)
The current UK Reference Nutrient Intake (RNI) for protein is 0.75 g per kilogram of body weight per day. This level is designed to prevent deficiency in healthy adults. However, preventing deficiency is not necessarily the same as supporting healthy ageing or preserving muscle.
Research increasingly suggests that many adults over 45 are likely to benefit from around 1.2 to 1.6 g of protein per kilogram of body weight per day, particularly if they exercise regularly, are trying to lose body fat, or want to preserve muscle during the menopause transition. For someone weighing 70 kg, this equates to approximately 84 to 112 grams of protein per day, with people who undertake more intensive strength training or endurance exercise potentially benefiting from even higher intakes, depending on their training goals.
It's not just about the total amount
How protein is spread across the day matters too. Think of protein as giving your muscles several opportunities to repair and maintain themselves, rather than asking them to do all the work after one evening meal. Aim to include a good source of protein with breakfast, lunch and your evening meal.
Examples include:
- Eggs or Greek yoghurt at breakfast
- Cottage cheese, chicken, tinned fish like sardines (basically a superfood!), tofu or beans at lunch
- Fish, lean meat, lentils, tofu or other protein-rich foods with your evening meal
If you’re trying to increase your intake, it’s often easier to make small improvements to each meal than to dramatically increase protein at dinner.
Is protein the whole answer?
Probably not. One of the reasons nutrition can feel confusing is that two people can eat similar diets and achieve very different results. Age, hormones, activity levels, sleep, stress and overall health all influence how our bodies respond to food.
Genetics may also play a part. Variations in genes linked to appetite, metabolism, body composition and exercise response can influence how easily we maintain muscle or regulate body weight.
That doesn’t mean our genes determine our future. In fact, many genetic tendencies can be strongly influenced by diet and lifestyle. But understanding those tendencies can sometimes help explain why one approach works well for one person but not for another. This is where personalised nutrition becomes valuable. Rather than relying on general advice alone, it considers the wider picture and helps tailor recommendations to the individual.
The bottom line
Protein isn’t suddenly important once we reach midlife. It’s always been important. The difference is that our bodies become less efficient at using it, while maintaining muscle becomes increasingly important for metabolic health, strength, mobility and healthy ageing. For many women, simply increasing protein intake, spreading it more evenly throughout the day and combining it with regular resistance exercise can make a meaningful difference.
If you’ve noticed that your body feels different than it did ten years ago, it’s worth remembering that this isn’t simply about willpower. Our physiology changes with age, and our nutrition often needs to change with it. The goal isn’t to follow the latest high-protein trend. It’s to understand what your body needs now, so you can continue to feel strong, active and healthy for many years to come.
