Photo by Dan Meyers on Unsplash
In short: Bio-individuality means that each of us needs something a little different to feel well. Your genes, your gut, your stress, your sleep, your age, your hormones, your activity and even your culture all change how your body responds to food. That’s why the way of eating that works wonders for your friend can leave you tired, hungry or bloated. Instead of following one more plan, you can find out what suits you with a simple two-week experiment.
Your friend swears by her morning porridge. You try it and you’re starving by ten. Your colleague feels amazing since she gave up coffee, while you can’t imagine your morning without it. Your sister felt great on a low-carb plan, and you just felt miserable and dreamed of bread.
Who’s right? All of you.
This is bio-individuality: the idea that each of us has different needs. I explained what bio-individuality is in an earlier article. Today, let’s look at what it means in real life, and how you can find out what your own body needs.
Why doesn’t the same diet work for everyone?
For years, we’ve been told there is one right way to eat. Low-fat, then low-carb, then intermittent fasting, then plant-based, then keto. Each one works brilliantly for some people and not at all for others. Those people don’t lack willpower. They’re simply different.
Many of us have always felt this, long before anyone wrote about it. Picture two women sitting at the same table, eating the same banana. One feels steady and satisfied for the rest of the morning. The other feels a quick lift, then a slump, and she’s looking for something sweet an hour later. Same food, two very different bodies. Even two sisters, raised on the same meals in the same kitchen, can react quite differently to the same plate.
So when someone tells you “this is the diet that works”, the honest answer is: it works for them.
What makes your needs different?
Your genes. They influence how you handle caffeine, milk, fats and even how much you enjoy bitter vegetables. Some people sleep like a baby after an espresso; others still feel it at midnight. Some people digest milk easily all their lives, while many others find it harder as adults.
Your gut. Everyone’s gut bacteria are different, a bit like a fingerprint. They affect how you digest fibre, how much energy you get from food and how you feel after a meal. My FAQs on gut health explain this in more detail.
Your stress and sleep. A tired, stressed body craves sugar and quick energy, and it handles food differently. After a bad night, most of us feel hungrier and less satisfied.
Your age and hormones. What worked in your thirties may not work in your fifties. In perimenopause and menopause, for example, many women need more protein and handle sugar less easily than before.
Your activity. Someone who moves all day, gardens or trains hard needs different fuel from someone sitting at a desk.
Your daily rhythm. Some people wake up hungry, others can’t face food before eleven. Some feel best with three meals, others with smaller ones more often.
Your health history. Food intolerances, medication, past illnesses and digestion all play a part.
Your culture, taste and memories. Food is also pleasure, family, tradition and comfort. A way of eating that ignores this won’t last, however healthy it looks on paper.
How do you know a diet isn’t right for you?
Your body gives you signals all the time. Here are some signs that a way of eating isn’t working for you, even if it works for others:
you’re hungry again an hour after eating,
you feel sleepy or foggy after meals, like the afternoon energy dip so many of us know,
you have regular bloating, heartburn or digestive trouble,
you crave sugar in the afternoon or evening,
your sleep gets worse,
you feel irritable, low or anxious,
or you’re constantly thinking about food.
None of these means you’re doing something wrong. They’re simply information. Your body is telling you something needs to change.
A simple two-week experiment
Instead of following yet another diet, become curious about your own body. Here is the experiment I often suggest when I start working with someone.
Step 1: Keep a food and mood diary
For the first week, don’t change anything. Just notice. Write down what you eat and drink, and when. Then, an hour or two later, note how you feel: your energy, your mood, your digestion and your hunger. A few words are enough, for example:
Eight o’clock: porridge with banana and honey, coffee. Ten o’clock: starving, a bit shaky, hard to concentrate.
Eight o’clock: two eggs, wholegrain toast, tomato, coffee. Half past eleven: comfortable, focused, not hungry yet.
Also note how you slept, how stressed you felt and how much you moved. These all affect how food makes you feel.
Step 2: Change one thing at a time
In the second week, choose one thing to change based on what you noticed. Only one, so you know what made the difference. For example:
swap a sweet breakfast for one with protein,
have your coffee after breakfast rather than on an empty stomach,
eat dinner an hour earlier,
add a portion of vegetables to lunch,
or leave out wine on weeknights.
Step 3: Notice your sleep
Does a late dinner, a glass of wine or a sweet dessert change how you sleep? Sleep is often where food shows its effects most clearly, and better sleep changes everything else. If you often wake in the small hours, I wrote about why that happens in midlife and what helps.
Step 4: Listen to your hunger
Before you eat, pause for a moment. Are you really hungry, or tired, bored, stressed or thirsty? There are many kinds of hunger, and my article on the seven kinds of hunger can help you tell them apart. And if your hunger tends to turn up in the evening, have a look at comfort eating in autumn. If you’d like to go further with this, intuitive eating is all about learning to trust these signals again.
Step 5: Look back after two weeks
Read through your diary with a cup of tea. You’ll probably see patterns you never noticed before: a food that always leaves you bloated, a time of day when your energy drops, a meal that keeps you going for hours. These patterns are your personal guide, and they are worth more than any diet book.
What mistakes should you avoid?
Changing everything at once. You won’t know what worked, and it’s very hard to keep up.
Judging yourself. Your diary is there to inform you. Nobody is giving marks.
Copying someone else’s results. What you discover is yours, and it may be different from your friend’s.
Cutting out whole food groups without a reason. If you suspect an intolerance or a health issue, talk to your doctor before removing foods for good.
Thinking it’s forever. Your needs will change with the seasons, your age and your life. That’s normal.
There is no perfect diet, only the right one for you right now
You don’t need to find one plan and follow it forever. What you’re learning instead is to listen to your body, understand its signals and adjust along the way. That’s a skill you keep for life, and it’s one of the most freeing things you can learn.
In yoga we talk about coming back to the body, again and again, with curiosity and without judgement. Your food diary is exactly that, on paper. When I work with someone, I always start here, with their own body and their own life, before I talk about any food at all.
Frequently asked questions
What is bio-individuality in simple words?
It’s the idea that there is no single diet that suits everyone. Each person has different needs depending on their body, health, age, lifestyle and preferences, so the best way of eating is the one that fits you.
Why do people react so differently to the same food?
Because no two bodies are the same. Your genes, your gut bacteria, your sleep, your stress, your hormones and how much you move all shape how a meal makes you feel, so the same plate can leave one person energised and another sleepy or bloated.
Do I need a DNA or gut test to know what suits me?
Not necessarily. Tests can give interesting information, but a careful food and mood diary, and paying attention to how you feel, already tells you a lot, and it costs nothing.
When should I talk to my doctor?
If you have regular digestive trouble, pain, unexplained tiredness or weight changes, or if you think you may have a food intolerance, please see your doctor before cutting foods out. The same goes if you take medication or have a health condition that food might affect.
Would you like some help?
Reading your body’s signals isn’t always easy on your own, especially when you’re busy, stressed or have tried many diets before. Doing it alongside others helps more than you might think: everyone discovers something different, and that’s the whole point. I run group programmes in nutrition and health, such as Six Tuesdays in Montignac. If you’d like to hear when the next group opens, write to me at hello@catherinepolet.coach.
Would you rather look at your own diary together, one to one? Book a free 20-minute call with me. I also coach online, so it doesn’t matter where you live. I’d love to help you discover what your body has been trying to tell you.
About Catherine
I’m Catherine Polet, a holistic nutrition health coach, yoga and autogenic training teacher for more than 30 years, author and speaker. I help people find a way of eating and living that suits their own body, online in English, French, Spanish and German, and in person in Southwest France.
