When it comes to losing weight, many of us are looking for the easiest option, if we're speaking truthfully. Countless diet books, fitness accounts, influencers and academic studies offer ways to do this, but one academic says that there is no easy way to lose weight, as so much of it depends on our genes.
"What I'm not promising is a diet plan", says Dr Giles Yeo, an obesity geneticist in Cambridge and author of Gene Eating, what he calls the "anti-diet diet book".
"My hope for this is two things, the first is that obesity is not a choice. And then the second bit is, there are a lot of diets out there that do work for many people, but not all diets work for everyone and if you want to lose weight, you've got to eat less. But you've got to have to find your own personal way to eat less because there's no magic diet that suits everybody."
Dr. Yeo's argument is that your genetic makeup has more control over your weight than we are led to believe, rather than whether or not you can resist that second doughnut of the day.
"Your genes influence your body weight more than you might actually imagine", he tells The Ray D'Arcy Show. "What we now know is there are over 200 genes - more than that, probably - and they influence our behaviour around food.
"So while the physics of it, meaning you've got to eat more in order to gain weight and you've got to eat less to lose weight, why do we behave differently around food? That has powerful genetic influences."
He explains that personal tastes and the foods we are individually attracted to make any attempt to reduce obesity by banning one or two foods less effective than you might think.
"There are some people out there you know love chocolate. Me, chocolate, it's okay. Pork scratchings, fried pig skin, I love. Whereas imagine a government edict coming down saying 'we're going to ban chocolate to cure obesity'. It's never going to work for me."
As well as this, our genes influence how hungry we feel we are. Dr. Yeo explains that there are some people who feel " a few percent more hungry" than others, which leads to excessive eating.
"If you actually ate 5% more at every meal because you feel that little bit more hungry, at some point you'll suddenly gain all this weight. I'm not talking about eating twice the amount of food."
His central argument is that when it comes to weight loss, "people are fighting their biology".
If people find it more difficult to say no to the impulses to eat certain foods more often, "is that really a choice", argues Dr. Yeo. "Obesity doesn't happen overnight, obesity happens over a long period of time, eating a little bit more every single day."
Beyond hunger, as we typically think of it, - the grumbling stomachs and shorter tempers, perhaps - "there is also hunger in a sense where you're more driven towards food", he says.
"For example, there are some people we know that when stressed stop eating, whereas there are other people who when stressed suddenly eat in order to make themselves feel better. It's the same hormone, it's cortisol."
How the brain reacts to signals and stimuli is central to weight management. "Your brain needs two pieces of information in order to influence your food intake", Dr. Yeo says. "It needs to know how much fat you have, because how much fat you have is how long you will last in the wild without any food. Then it needs to know what you have just eaten and what you are currently eating."
"Imagine if your brain is slightly less sensitive to these signals. For example, if you were carrying 20 kg of fat, but your brain only senses 18 kg it will drive you to eat more to get the 20 kg, even if you already have it, making you larger."
So what are we doing differently now than our ancestors, who were not as obese, according to research?
"The reason is because the environment, our diet, our lifestyle, the fact that we don't move as much - that has undoubtedly driven the obesity epidemic.
"Our genes have not changed, the genes interacting with the environment has changed."
For example, Dr. Yeo references the "protein leverage hypothesis", where humans will prioritise getting the 15% of protein they need to build strong muscles and grow, even if that protein comes from more processed and less wholesome food. This could lead to eating unhealthy food, which over time will lead to weight gain.
"I'm not trying to give anyone an excuse, although some people may take it as an excuse. I'm just trying to understand the biology of the system so we can try to fix the problem."
What complicates it further is the narrative peddled by social influencers, Dr. Yeo says.
"They're largely pretty ladies with six packs and I have a one-pack so this is not me. What they do is ... there is someone who is ill, they change their diet, suddenly they become well, suddenly they start a social influencer site."
He says that these narratives leave aside the fact that they are "probably privileged, their genes make them look pretty" and their original diet probably had little to do with the condition they wanted to cure".
People like to see a "pretty image ... and an easy answer", he says, but "there are no easy answers to losing weight".
To listen back to the full interview, click the video above!
