Exercise to lose weight: what training can do, and what it needs from your plate

Why training alone moves the scale slowly

A session burns real energy. According to the CDC, a person of 70 kilograms uses about 280 kilocalories in an hour of walking at 3.5 miles per hour, and about 590 in an hour of running at 5 miles per hour. Those are useful numbers. They are also smaller than a single restaurant dessert, which is why an evening of training can be undone in ten minutes at the table.

There is a second reason. In a study of 332 adults across five populations, Pontzer and colleagues measured total daily energy use and found that it rose with physical activity at lower levels, then levelled off at higher levels. The body seems to adjust elsewhere when activity climbs. Exercise still counts, but its effect on the energy balance is not a simple addition of the numbers on your watch.

None of this makes training pointless for weight. It changes the role it plays: exercise protects muscle, improves health markers even without weight loss, and, as we will see, matters most for keeping weight off.

The dose that shows up on the scale

The ACSM position stand led by Donnelly gives the clearest dose figures we have.

• 150 to 250 minutes a week of moderate activity helps prevent weight gain and gives a modest loss.
• More than 250 minutes a week is associated with clinically significant weight loss.
• Combined with a moderate diet, 150 to 250 minutes improves weight loss. Combined with a severe diet, it did not.

The NHS starts at the same place: get active for 150 minutes a week, broken into shorter sessions if needed. That is the World Health Organization minimum for health too. If you are starting from little, those 150 minutes are the first target, and how much exercise per week explains how to reach them. The 250 minutes come later, and walking counts towards them: see daily steps.

Food does most of the subtraction

The CDC page on physical activity and weight is direct: losing weight and keeping it off with activity alone needs a high amount of it, unless you also reduce the calories you eat and drink. In practice, the larger share of a weight loss comes from the plate, and exercise makes that loss better quality.

Start by estimating what your body uses in a day. The calculator on this page applies the Mifflin-St Jeor equation, which a 2005 systematic review by Frankenfield and colleagues found to be the most reliable of the common equations, predicting resting expenditure within 10% of the measured value for more people than any other. Take an illustrative case: a man of 42, 85 kilograms, 178 centimetres, training lightly. The equation gives about 1,760 kilocalories at rest and about 2,420 for the whole day.

From there, a small, steady reduction is enough. The method, and the size of deficit the guidelines suggest, are in calorie deficit. The guide to calorie needs explains how to choose your activity factor honestly.

Strength training: keeping the weight you want to keep

When you eat less, part of what you lose can be muscle. The ACSM position stand found that resistance training does not enhance weight loss on the scale, but may increase fat-free mass and the loss of fat mass. In other words, lifting changes what the lost weight is made of.

That matters for two reasons. Muscle keeps you strong as the years go by, and it is part of what sets your resting energy use. Two sessions a week covering the main movements are enough to start. The guide to strength training for executives gives a simple structure, and protein for weight loss covers the food side of keeping muscle.

Cardio, intervals or weights?

The best form is the one you will still be doing in six months. Brisk walking, cycling, swimming, rowing and circuit training all count towards the weekly minutes. Intervals save time but are harder to repeat often; short, hard workouts describes what they can and cannot replace.

A sensible mix for most adults:

1. Two strength sessions a week, full body, 30 to 45 minutes.
2. Two or three aerobic sessions, at a pace where talking becomes harder but stays possible.
3. Walking every day, which adds up without fatigue and is easy to raise towards 250 minutes.

Exercise also reduces the fat stored around the organs, sometimes before the scale moves. The evidence is set out in lose belly fat.

What to expect, week by week

The NHS suggests aiming to lose 0.5 to 1 kilogram a week, and the CDC notes that people who lose weight at a gradual, steady pace of about 1 to 2 pounds a week are more likely to keep it off. Some weeks will show more, some nothing at all: water, salt and the timing of meals move the scale from one morning to the next, independently of fat.

Judge the trend over three or four weeks, not the reading of a single day. If the trend is flat for a month, read weight loss plateau before cutting food further. And remember what the guidelines value: the 2013 American guideline on obesity notes that even a sustained loss of 3 to 5% brings clinically meaningful health benefits.

If you have heart disease, diabetes, high blood pressure, joint pain or a large amount of weight to lose, talk to your doctor before you raise your activity sharply. Stop and seek advice if you feel chest pain, unusual breathlessness or dizziness during exercise.

The habit is what produces the result

Every figure above depends on one thing: doing the sessions week after week. A plan of 150 minutes kept for six months will do more than 400 minutes kept for three weeks. That is why regularity, not intensity, deserves your attention first. Fix your sessions as appointments, keep a short version for difficult weeks, and add walking wherever the day allows.

Start this week with Never Skip Club

Never Skip Club is built for exactly this: turning good intentions into sessions that actually happen. Create your free account, launch a guided workout built in a minute for your level, your time and the equipment you have, and form a crew of three to seven friends with a rhythm you choose, for example three sessions a week. The ranking rewards regularity, not extra sessions, which is what weight loss needs. If you want an expert eye on your plan, find a coach from our network, or sign in to book your next session.