The Healthy Food Guide team believe that making small diet and lifestyle changes brings the best long-term gains. We look at the science behind the headlines and promote a balanced way of eating.

Weight loss slowed down? You could be on a weight loss plateau. Registered nutritionist Dr Sarah Schenker leads you off it with four simple tips*


How many times have you read that to lose 1lb you need to create a calorie deficit or shortfall of 3,500 a month? But, as many dieters have discovered, while the pounds melt away over the first, second and even third week, eventually this formula stops working and weight loss reaches a frustrating plateau.

1. Reassess your eating habits
Have portion sizes crept up? Have you relaxed your snack rules? Are you back on the wine?

2. Boost your activity
If you run, for instance, increase your pace or distance.

3. Accept that you need fewer calories now
If you were 10kg heavier before you started your diet, think of it as if you were carrying a 10kg bag of potatoes everywhere – extra energy was needed to move around with it. You’ve put the bag down now, so imagine how much less energy you need to move.

4. Understand weight loss inevitably slows down once you reach a healthier weight
Your achievement during those first few weeks was down to loss of fluid and some fat and was extraordinary. In fact, anything over 1lb a week is a bonus, not the norm. Losing even half a pound a week now is something to be proud of.

Why do plateaus happen?

The 3,500 calorie rule is based on a 1958 calculation originating from researcher Max Wishnofsky. He concluded the calorie equivalent of 1lb of body weight lost or gained was approximately equal to 3,500 calories. Until recent years, his findings were taken as read within the nutrition world and used as the basis for counselling patients who needed to lose weight. Now we know this is too simplistic.

The new maths

How much we need to reduce our calorie intake by ranges from 170 to 250 calories a day for a loss of 10% of our body weight, and from 325 to 480 calories a day for a 20% weight loss. OVer time if you continue to cut out 500 calories a day, it will have a smaller impact, so your rate of weight loss will slow down. This is when you find you need to restrict your calories further or burn more calories by exercising more in order to continue losing weight at the same rate.

How it works

If you weigh 15st and consuming 2,600 calories a day keeps you at this weight. By reducing your intake by 500 calories to 2,100 calories a day, you manage to lose 20% of your body weight to reach 12st. Your body now only needs 2,100 calories to stay at 12st, so if you stick with the 2,100 calories a day, you’ll maintain this weight – but you won’t lose much more. If this was your target, fantastic – but if you have more to go, it will probably leave you feeling demoralised.

What’s the new rule?

New weight-loss models have now been developed to replace the 3,500 calorie rule. These take into consideration body composition, age, height, gender and degree of calorie restriction. We like the energy balance calculator available for free on the Pennington Biomedical Research Center website. These new models result in a more flexible pattern of weight loss over time, rather than the ‘set in stone’ 1lb a week loss predicted by the 3,500 calorie rule. They also show this rule is only valid (at best) for the first month after starting a diet.

Do we need a total rethink?

Although the 3,500 calorie rule may not follow a perfect downward line in the long term, it continues to be a good starting point. After that, the speed at which an individual shifts any excess pounds will depend on many different things, including your starting weight, body composition (how much muscle you have, for example), gender and age.

Cutting 500 calories a day remains reasonable and achievable for most people – cut calories too dramatically and, while weight loss may initially be faster, your diet is likely to be far more limited, so you’ll find it harder to stick to and probably give up. Just be prepared to be flexible and adjust the 500 calorie figure the closer you get to your target weight.

And in today’s obesogenic environment, it’s also worth remembering that maintaining our weight should also be celebrated! Give yourself a pat on the back and remember – your journey may be slower from now on, but the results should be longer-lasting because you’ve made sensible changes you can stick to in the long run.