There are lots of misconceptions about the best ways to lose weight. One of the biggest questions is whether we need exercise to lose weight or not. The type of diet and type of exercise is important to consider alongside individual characteristics.  

For our weight to stay stable, the energy we put into our bodies must be the same as the output energy we use for our bodily functions and physical activity. An imbalance of energy intake and energy expenditure can affect our weight. A positive energy balance occurs when energy intake is greater than the energy expenditure. Long-term positive energy balance can result in weight gain. A negative energy balance is when energy intake is less than the energy expenditure, which can result in weight loss (5).

The National Institute for Health and Care Excellence recommends that the main requirement for dietary approaches to weight loss is that total energy intake should be less than the energy expenditure (negative energy balance). They state that diets with 600kcal deficits are recommended for sustainable long-term weight loss plans. This means the daily calorie intake should be 600kcal less than what would be needed to stay the same weight (6).

Multicomponent interventions and recommended for the best weight management outcomes. This should be a combination of dietary modification (improved quality and reduced energy intake), increased physical activity/ a decreased inactivity and behaviour change strategies (6).

Review of evidence

One review assessed weight-loss interventions for postpartum women with diet alone, diet and exercise or exercise alone. Those receiving any form of diet were involved in a calorie-restricted diet, with some trials also receiving nutrition education. Those required to exercise were involved in aerobic exercise programmes that were either self-monitored or supervised.

The women who took part in a diet or diet plus exercise program were found to lose significantly more weight than those conducting their usual dietary and lifestyle behaviours. Those who exercised alone did not lose significantly more weight than those in usual care. This evidence suggests that diet and exercise together or diet alone can help women to lose weight. Exercise alone seems to have minimal effect on weight loss (1).

Other benefits of exercise

Exercising can have other benefits alongside weight loss and reducing the risk of obesity. Being active can reduce the risks of having long-term health conditions (4).  

One health benefit of exercise is the improvement of cardiovascular fitness. Regular physical activity can keep your heart healthy and reduce the risks of coronary heart disease, stroke and developing high blood pressure. Cardiovascular activity, known as aerobic cardio, is the type of exercise that can keep your heart healthy and circulation healthy (2,4).

It is also known that exercise can reduce the risk of type 2 diabetes. Being inactive and overweight is a risk factor for developing type 2 diabetes. If you have type 2 diabetes, regular exercise can help to keep your blood glucose levels within the target range and help manage insulin (2,4).

Exercise can lower the risk of developing certain types of cancer, including breast and bowel cancer. If you are diagnosed with cancer, exercise can also be helpful to reduce some side effects of treatment and reduce tiredness (2,4).

Regular physical exercise can help keep your muscles, bones, and joints healthy. This can help reduce the risk of conditions such as osteoarthritis, and hip fractures (2,4).

Exercise can also improve cognition and health-related quality of life with a reduced risk of anxiety and depression (3). It can also reduce the risk and onset of dementia. Regular exercise can also improve the quality of your sleep. There are also social benefits associated with exercise with an increase in mood and wellbeing. Social connections can be formed through exercise and a reduced feeling of isolation (3).

The figure below comes from Public Health England, which outlines the health benefits of physical activity and the percentage decrease in the health risks (7).

Figure 1: Health Benefits of Physical Activity


Evidence shows that weight loss can be achieved from a variety of different dietary interventions, whether this is long-term or short-term. For weight management to be effective, there must be short-term and long-term goals/plans. If this is not in place, there is likely to be weight regain. Every individual responds differently to different diet and exercise interventions (8).

It is advised that a combination of dietary and exercise interventions should be used. This is due to the promotion of a negative energy balance and the improvement of other health-related risks with exercise.

If you are beginning your weight loss and/or exercise journey, and need some structure to achieve your goals, book a session with one of our dietitian specialists to get individual and tailored advice.

By Elsie Cole, Dietetic student, revised by Reema Patel, Registered Dietitian at Dietitian Fit & Co