Cut Calories to Increase Quality and Length of Life

by Ashleigh Feltham,  Accredited Practising Dietitian and Accredited Nutritionist

Do you want to live a longer and healthier life? More than likely, you answered yes. While there are many factors out of your control, new research suggests that cutting back on calories could not only increase your quality of life but also your length of life.

A new study found that moderately reducing your total calories (but not to the extent of malnutrition) has beneficial effects on both your health and lifespan. Researchers investigated the effects of reducing total calories by 14% over a two-year period. They also looked at the effects of a 40% reduction of total calories in mice.

Cut Calories to Increase Quality and Length of Life

Researchers found there was an improvement to the thymus gland, a type of lymphoid organ that plays a critical role in optimising immune system function. The thymus secretes the hormone thymosin, which is needed for the immune cells, called T-cells, to mature. T-cells play an important role in fighting off pathogens and removing damaged cells in the body.

Platelet-activating factor acetylhydrolase (PAF-AH) has a powerful influence on inflammation and allergic response. PAF-AH was reduced in people who reduced their total calorie intake. One of the causes of chronic disease and ageing is due to long term inflammation in the body. Reducing PAF-AH may promote greater longevity.

The positive effects of a reduction of PAF-AH was also seen in the mice study. Improvements to the function of the thymic gland and certain metabolic functions resulted when the gene to create PAF-AH was deactivated. Researchers hypothesised a reduction in calories may promote a reduced expression of the gene that creates PAF-AH and may consequently be a mechanism for improvement in both health and lifespan.

Reducing your calorie intake is likely going to cause some level of hunger while your body adjusts. One helpful strategy is to include fibre rich foods in your meals and snacks. Fibre slows the absorption of sugar in the gut and helps provide sustained energy. This also helps to make you feel fuller for longer and reduce feelings of hunger.

Foods rich in fibre can be found in plant food like wholegrains, nuts, seeds, legumes, fruit and vegetables. Aim to fill half of your plate with vegetables and a quarter with wholegrains. Snack on vegetables and fruit, and supplement your diet with good sources of inulin. Inulin is a prebiotic fibre that supports a healthy gut.

Take home message:

Cut Calories to Increase Quality and Length of Life. Living a longer and healthier life may be well within your control. Removing excess calories could be a key factor. Including fibre reduces hunger and promotes healthy weight loss and maintenance.



  1. Timothy W. Rhoads,Rozalyn M. Anderson, Caloric restriction has a new player, Science, 375, 6581, (620-621), (2022)./doi/10.1126/science.abn6576
  2. Liu, G., Kaneko, M., Yoshioka, K. et al. Platelet-activating factor (PAF) strongly enhances contractile mechanical activities in guinea pig and mouse urinary bladder. Sci Rep 12, 2783 (2022).