Cardio or weights for weight loss: strength first.

Six in the evening, the gym, an hour to spare. You wonder yet again whether cardio or weights is better for losing weight, then get on the treadmill and stay there until time's up. The weights programme stays folded in your bag.

It's the choice I see most often. The treadmill makes you sweat, the screen counts the calories, and weights look like something for people who want big arms. After 40 that order needs turning round, for men and women alike.

How to tell cardio alone isn't enough

These are the usual signs.

• The scales move, the mirror doesn't. You weigh less, but your belly hasn't changed.
• Weak arms. The suitcase, the shopping bags, a press-up. Everything feels heavier.
• You're stuck. Same minutes and same speed for months, same weight.

Is cardio or weights better for weight loss?

You need both, but weights come first. Cardio burns calories while you're doing it. Weights help you lose fat and hold on to muscle.

Your body keeps what it uses. When you eat less, your body takes energy from wherever it can, muscle included. Make that muscle work against a load and your body gets the message that it's needed, so it draws more on fat. The opposite happens in a hospital bed, where muscle goes quickly.

You adapt to cardio fast. Your body learns to do the same work for less energy, and it saves elsewhere. You move less for the rest of the day without realising, and you get hungrier. That's why adding cardio on its own often does little for your weight.

Muscle isn't a furnace. An extra kilo of muscle raises what you burn at rest by about one and a half per cent. Not much. The real gain is indirect. The stronger you are, the harder you can train, and afterwards your body keeps burning more for a few hours.

What to do, and in what order

Two strength sessions a week, before anything else. Whole body, with loads that challenge you. Around the menopause they matter even more, because muscle and bone are lost faster and proper loads do more than hours of moderate cardio. I explain how to build these sessions in the article on having no time to exercise. And have protein at every meal.

Cardio or weights first? Weights. In the same session, lift while you're fresh and leave cardio until the end. Turn up to the weights already tired and you lift less, so the session does less for you. If you can, put them on different days.

Walk, every day. Seven to eight thousand steps, plus ten to fifteen minutes after meals. It's the cardio that's kindest to muscle, and it doesn't eat into your recovery from the weights. At the right pace you can talk in full sentences but couldn't sing.

Fifteen hard minutes, once a week. Running or on a bike: one minute hard, one or two easy. It builds aerobic fitness, meaning how much oxygen you can use when you're working hard. Better aerobic fitness is linked to a longer life.

Next session, take the programme out of your bag and start with the weights. The treadmill gets whatever time is left.