From sugar to sleep: Harvard-trained gut doctor shares 6 anti-aging lessons he wishes he knew in his 20s

Ageing is a natural process, but the choices made in everyday life can influence how the body ages over time. From what goes on the plate to how well a person sleeps, manages stress and stays physically active, several lifestyle factors are closely linked to healthy ageing. Understanding these connections early can help build habits that support long-term health rather than relying only on anti-ageing fixes later. Harvard-trained gut doctor Dr Saurabh Sethi has shared six such lessons on Instagram, highlighting the role of diet, gut health, stress, sleep, muscle and healthy fats in supporting longevity and overall wellbeing.

Sugar can affect collagen

Excess sugar can contribute to a process called glycation, in which sugars bind to proteins such as collagen and elastin, forming advanced glycation end products (AGEs). These compounds can alter collagen’s structure and properties, potentially contributing to changes associated with skin ageing. Dr Sethi suggests replacing one sugary drink a day with water, unsweetened green tea or coffee as a simple way to cut down on added sugar.

Gut health matters for skin

The gut and skin communicate through what is often called the gut-skin axis. Research suggests that the gut microbiome can influence immune responses and inflammatory pathways that are relevant to skin health. Dr Sethi recommends regularly including fermented foods such as yoghurt, kefir, kimchi or sauerkraut as part of a varied diet.

Stress can affect cellular ageing

Chronic psychological stress has been associated with changes in telomere biology. Telomeres are protective structures at the ends of chromosomes, and research has explored their relationship with cellular ageing and stress-related health effects. To make stress management more achievable, Dr Sethi recommends trying three minutes of slow breathing before bedtime.

Muscle is an ageing asset

Maintaining muscle becomes increasingly important with age because declining muscle mass and strength can affect mobility, physical function and independence. Resistance training is considered an effective strategy for helping counter these age-related losses. Dr Sethi recommends strength training at least twice a week, with exercises such as squats, push-ups and resistance-band movements.

Healthy fats support cells

Omega-3 fatty acids are not simply dietary fats; they are important components of cell membranes and play roles in several signalling processes in the body. EPA and DHA are found mainly in fatty fish and seafood, while ALA comes from plant foods such as flaxseed and walnuts. Dr Sethi suggests including fatty fish regularly or choosing plant-based sources such as walnuts, chia and flax for ALA.

Sleep supports healthy ageing

Sleep is essential for several aspects of health, including metabolic, immune and emotional wellbeing. The CDC recommends that adults aged 18–60 get at least seven hours of sleep each night. Dr Sethi recommends aiming for 7–9 hours and maintaining consistent sleep and wake times, making adequate rest an important part of a long-term healthy ageing routine.