A health professor and personal trainer shares the 3 things she never skips so she can stay fit, happy, and healthy

• Devi Sridhar is a professor of global public health and a personal trainer.
• She told Insider her three non-negotiables for staying fit, healthy, and happy.

As professor of global public health at the University of Edinburgh, UK, Devi Sridhar knows a thing or two about staying healthy.

Wanting to further her passion for fitness by teaching classes, Sridhar qualified as a personal trainer in 2022, she told Insider. As the world emerges from the grips of the coronavirus pandemic, Sridhar's work currently focuses on"COVID recovery": helping to rebuild global health after the unprecedented event.

The health divide has grown since the pandemic, and in many ways we have gone backwards, Sridhar said: "The fit have got fitter but those who were struggling are struggling even more."

Sridhar believes staying healthy by following a nutritious diet and keeping fit are the most important things people can do to stay healthy, in turn helping to create a more robust and resilient population, and reducing the strain on health services.

Sridhar shared her own non-negotiables when it comes to staying healthy with Insider.

1. A good night's sleep

Sleep is a priority for Sridhar.

Staying up late can be detrimental to our health, with research finding links between going to bed after 10 p.m. and poorer heart health. So getting to bed at a decent time is key part of Sridhar's healthy lifestyle, she said.

If Sridhar is feeling tired in the evening but still has work to do, she goes to bed then gets up early to finish her work, she said.

2. Moving for 20-30 minutes a day

Sridhar tries to move for 20-30 minutes every day, she said. This doesn't need to be a big workout though — she gave the example of walking around an airport recently when she had time to kill.

However, qualifying as a personal trainer taught Sridhar the importance of resistance training, particularly as you get older, she said.

Whether lifting weights or using your own bodyweight, strength training has many benefits, such as reducing the risk of osteoporosis, or even reversing it.

3. Eating a diverse diet

Sridhar tries to eat a diverse diet, which she says is hard when you're busy or travel a lot like she does.

Even if Sridhar doesn't always eat a "healthy" diet, she tries to eat a range of foods and food groups rather than just carbs, she said.

Sridhar also recommended avoiding ultraprocessed foods and sodas.

Ultraprocessed foods — those with long ingredients lists which usually come in packaging — are often easy to overeat and aren't satiating, she said.

Sodas are generally full of sugar, containing more than you would eat in a food, and sugar-free ones with artificial sweeteners often lead to sugar cravings, Sridhar said.

Relationships are important for health and happiness too

As a bonus point, Sridhar encourages people not to forget about maintaining good social relationships when thinking about their health. Research shows that people with stronger connections to others have a lower risk of death, as Insider's Hilary Brueck reported.

"When people talk on their deathbeds over their life, they talk about relationships and people, and I think that's what gives us joy," Sridhar said.

While society may focus on external status symbols, Sridhar said it's the people in our lives that make us happy, from family, friends, and romantic partners, to acquaintances you see in the gym or grocery store.

Elderly people who have strong social connections tend to be healthier and more engaged, she said.

"We focus a lot on needing to achieve and being successful, but actually being successful can be having a really strong social network," Sridhar said.