A new study published in the British Medical Journal (BMJ) today reveals that those who have had a lean body shape over a consistent period of time tend to live longer as compared to those with a high body mass index (BMI) since early childhood and all the way up till middle age.

To assess the results, five different body shapes were taken into account ranging from the age group 5-50 of 80,266 women and 36,622 men. These five body shapes included: lean stable, lean-moderate increase, lean-marked increase, medium-stable/increase and heavy-stable increase. Participants were asked to recall their body shape during the course of their lifetime from when they were 5, 10, 20, 30 and 40 years of age.

Results concluded that 35% of women and 25% of men managed to sustain themselves by falling in the lean stable group throughout the course of their lifetime. Furthermore, 29% of women and 17% of men started off by being lean but then gained a moderate level of weight and eventually fell in the lean-moderate increase group. Also, 11% of women and 17% of men were initially lean but then gained a considerable amount of weight and became a part of the lean-marked increase group. It was also discovered that 19% of women and 28% of men had a medium body shape but then gained weight over a period of time thus falling in the medium-stable increase group. And lastly, 6% of women and 13% of men started out by being heavy and then continued to be heavy or gain further weight and were thus considered to be from the heavy-stable/increase group.

Moreover, those who were heavy during their childhood and maintained this weight uptil middle age or gained further weight were at an increased risk of death of up to 15 years by 19.7% in women and 24.1% in men.

Along with that, a widespread range of causes concerning death apart from overall mortality was also studied. Participants were asked to fill in comprehensive questionnaires regarding their lifestyle and medical information after every two years to get the latest results. Diet was also assessed through the use of validated food frequency questionnaires after every four years. Subjects who had suffered from cancer or had a history of diabetes and cardiovascular diseases before the age of 50 were not included in the study.

Results displayed that those who had a history of type 2 diabetes and a heavy body shape were at an increased risk of death as compared those who did not have these problems. The diabetic patients were also assessed in terms of their smoking. Participants were divided into groups: those who were ‘ever smokers’ and those who were ‘never smokers’. Smoking tends to be the leading cause for premature death and various other diseases but in general smokers have a lower BMI than non smokers. The lowest recorded BMI for smokers was in the range of 20-22.

Comparison With Other Studies

Similar studies with a few changes here and there have been carried out before. One such study took place in 1998 where participants were presented with nine pictorial diagrams developed by Stunkard et al and they had to pick the one that was the closest to their body shape. As some participants were already older, a complete picture was not present in order to appropriately study their lifespan.

Strengths And Limitations Of The Study

First and foremost, the way body type was assessed through questionnaires by recalling is prone to subjective errors and biases. A more error free approach would be to assess people’s body shape and body mass index across their lifespan until their death but such an approach is not feasible and practical. However, a limited number of trajectories were formed with smoking and other prediagnostic illnesses not being recorded which are linked to causing fluctuations in weight change, thus not depicting a completely accurate representation of each individual’s body shape. Nonetheless, the trajectory method is up to date with the technological advancements taking place, thus making it easier for clinicians to incorporate these results for the practical use of this knowledge and implementation. Further work needs to be done nonetheless to take other relevant measures into account other than the BMI to gain a complete understanding of the situation.

A substantially heavy body shape all through childhood and middle age with a predominant rise in weight in middle life was linked with higher mortality rates whereas a lean body shape sustained for a stable period of time is associated with low mortality. The results of the study emphasize the need for having a balanced body weight throughout our lifespan starting from a very early age indicating the importance of weight management which would be beneficial in order to have a healthy lifespan.