Insulin resistance: the early signs you can act on.

The symptoms of insulin resistance, when your cells respond poorly to insulin, are mid-morning hunger, heavy sleepiness after lunch, sugar cravings and a waist that grows while your weight stays the same. They appear years before your blood sugar leaves the normal range.

You have a call at 8 am, lunch in front of the computer, and by 2 pm you are reading the same line three times. I see it often in the people I work with: the blood tests look fine and the body says something else.

What are the symptoms of insulin resistance?

They matter together: on its own, each one can have another explanation.

• Hunger and sugar cravings. An hour after a plate of pasta you are hungrier than before, and mid-afternoon you look for something sweet.
• The crash after lunch. You sit back down at your desk and your mind switches off.
• A waist that grows while your weight stays the same. It has a name: normal weight but metabolically obese.

How do you know if you have insulin resistance?

From the signs, your measurements and your blood tests, read together by your doctor. Blood sugar on its own shows up late: your pancreas compensates with more insulin, and the reading stays in range for years.

Ten or twenty years ahead. It can come before type 2 diabetes by up to twenty years, and it tends to get worse with age: the same insulin achieves less. That is why it is worth checking in your fifties, while nothing shows up yet.

What gets checked. Fasting blood sugar and fasting insulin, HbA1c, triglycerides and good cholesterol, plus your waist, which I cover in the article on belly fat after 40. No single number is a verdict.

What to do about insulin resistance, from movement to meals

Muscles come first. After a meal, your muscles are the first place the sugar goes: if you are sensitive it goes in there, if you are resistant it ends up in fat, which sends it to your liver. In one comparison, cardio plus weights three times a week, 45 minutes each, beat either one on its own.

Being regular beats being intense. One week of cardio already improves your sensitivity, whether you are 20 or 70. And you lose it quickly: seven days of sitting still raised the insulin needed for a sugar load by 53%. Never go two days in a row without moving.

Eat sitting down, away from screens. In a group followed for years, the people who ate in a hurry in front of a computer developed insulin resistance in 12.5% of cases, against 1.2% of those who ate calmly.

Watch insulin, not only sugar. There is a scale that measures how much insulin each food raises, with white bread set at 100: potatoes 121, yoghurt 115, pasta 40, eggs 31. Cakes and pastries raise it far more than they raise blood sugar. And keep the order on your plate, vegetables and protein before the carbohydrates, as I explain in the article on blood sugar spikes.

Your nights. Seven or eight hours is the range with the lowest risk, and every hour less raises that risk by 9%. Five short nights in a row lowered insulin sensitivity by 29%.

The mistake nearly everyone makes. Cutting out bread and pasta and leaving the rest: five-hour nights, rushed lunches, weeks without training. Insulin alone does not decide your weight: how much you eat and how much you move are what count.

Start with one thing this week: lunch sitting down, or the weights session.