Losing fat after 40

Your metabolism probably hasn't slowed as much as you think. What has changed is how much muscle you carry, how much you move, and how well you sleep. Fix those and the scale moves.

The metabolism myth

A large 2021 study in Science measured energy expenditure in more than 6,000 people aged 8 days to 95 years. Once the researchers adjusted for body size and muscle, daily energy use held remarkably steady from about age 20 to 60, and only started to decline after that.

So when a 45-year-old says he eats the same as he did at 25 and gains weight, the usual culprits are less muscle, less daily movement (fewer steps, a desk job, kids' schedules), more alcohol and worse sleep, not a broken metabolism.

What really changes

• Muscle gets harder to keep. Without strength training, men gradually lose muscle from around their 30s onward, and the rate picks up later in life. Less muscle means a lower calorie burn and a softer look at the same weight.
• Muscle responds less to protein. Older muscle needs a larger dose per meal to get the same building signal.
• Testosterone drifts down. Levels typically decline slowly with age. Excess body fat, poor sleep and heavy drinking push them lower; losing fat and lifting tend to help.
• Recovery is slower. Joints and sleep need more respect, which matters for how hard you cut and train.

The plan

1. Set a moderate deficit

Aim to lose 0.5 to 0.75% of your bodyweight a week. For a 220 lb man that's roughly 1 to 1.5 lb. Faster cuts cost more muscle, and muscle is the thing you can least afford to lose now. The calorie calculator gives you a starting target, and the cut planner shows how long it'll take.

2. Eat more protein, spread out

Target about 2 g per kg of goal bodyweight a day, in three or four meals with 30 to 50 g each. Front-load it: most men under-eat protein at breakfast.

3. Lift three times a week

Full-body sessions built on a squat or leg press, a hinge (Romanian deadlift or hip thrust), a press and a row. Two to four hard sets each, leaving a rep or two in the tank. The goal during a cut is to keep your strength, not set records.

4. Walk more

Daily steps are the most underrated fat-loss tool for men over 40. They burn meaningful calories without hurting recovery. If you're at 4,000 a day, getting to 8,000 to 10,000 can matter as much as your diet changes.

5. Protect your sleep and watch the drinks

Short sleep increases hunger and makes the deficit feel harder. Alcohol adds calories and tends to lead to worse food choices; cutting back is often the single biggest easy win.

What progress looks like

Weigh most mornings and compare weekly averages. Measure your waist at the navel every two weeks; if it's shrinking while your strength holds, you're losing fat and keeping muscle, even when the scale is slow. A body tape measure makes that easy, and our body fat calculator turns the measurements into an estimate.