Health and fitness are, obviously, pretty important, but cultural imperatives such as achieving a “summer” body that you can flaunt on the beach can have little to do with either. (And I say that as someone who’s written a few articles thereon, however well-intentioned.) Indeed, exercise and eating well may seem inherently good, but can, in excess, be problematic. What might be a healthier goal, then, is achieving a better body image: not a shirtless social media post, but rather the picture of your body that you form in your own mind. Because you can conform to society’s lean and muscular male beauty standard and still feel crap: I once transformed my body for pictures in a magazine – but the picture of it in my mind, not so much. And chances are it’s your mind, not your body, that could do with a transformation.

“Thinking about what your body does, not how it looks, can be a step towards feeling more positive about it,” says Professor Charlotte Markey, professor of psychology and health sciences at Rutgers University at Camden, New Jersey, and author of The Body Image Book For Boys (which is also helpful for men). Indeed, you can’t take a step anywhere, or feel anything, without your body – which, when you think about all the things it can do, is pretty amazing. A study (of women) found writing down 10 bodily functions, so to speak, and how those contributed to wellbeing, improved body image. There’s your first one…

“Make a list of body parts that you like or can appreciate,” Professor Markey says. Then run through it when you catch yourself being self-critical, or even daily when you perform a baked-in habit, like, say, brushing your teeth (however you may feel about them).

While not caring at all about your appearance likely won’t serve you, neither will caring too much. How much time and energy you devote to it is, says Professor Markey, your choice. Either way, you should try to live what you value. So, ask yourself: what do you value? Appearance or health? What do you want to achieve in life? What you want others to value about you? Do you care about people in your life because of how they look, or for other reasons? Do you really want to take your values from industries that don’t value you?

Acceptance and commitment therapy (ACT) suggests you’re more motivated to meet – and be satisfied by – goals that reflect your values. Whereas if exercising for a flat stomach doesn’t align with your yen for, say, connecting with others, then “you’re less likely to want to do or enjoy the process,” says Mr James Downs, a yoga teacher and trainee counselling psychologist who found ACT helpful while recovering from an eating disorder.

Framing exercise as an obligation – or punishment – won’t make you enjoy it or be more inclined to do it either, says Professor Markey. So reframe it as a form of self-care, something good for your health, even something that makes you feel good (even if only afterwards). Health-based motivations for exercise are associated with greater exercise consistency than appearance-based.

A robust body of evidence shows exercise and eating well can bolster physical and mental wellbeing. “But things can go too far,” says Mr George Mycock, whose experience of eating disorders and muscle dysmorphia – a pathological preoccupation with muscularity – led him to found the organisation MyoMinds. (“Myo-” means “of or relating to muscles”). The MyoMinds podcast features discussions with experts by education and experience (and, full disclosure, this author). The book Orthorexia by sports dietician Ms Renee McGregor, who works with athletes who’ve developed unhealthy relationships with food, gives a good explanation of how striving to eat “clean” can go bad.

The media can make it seem that only one type of body is desirable, even acceptable (cough, Love Island). Conversely, the real world is populated by an abundance of body types that don’t all debar their inhabitants from success, romance, happiness. Uncomfortably deterministic though it may sound, some of us are more predisposed to build muscle and burn fat (and wind up working in body-driven industries) than others. “Set point theory” holds that our bodies want to hover within their own differing, genetically determined weight range. You can’t, says Professor Markey, necessarily determine someone’s health or habits from their body. Yes, you can dramatically change your body through exercise and diet – but only within set parameters like height and frame. And does the outcome really merit so much time and effort? That’s for you to decide.

“To me, ‘healthy’ doesn’t look like the cover of a fitness magazine or the edited images flooding Instagram,” says personal trainer Mr Al Jackson, who advocates being “body neutral” (see number 33). In fact, says Jackson, such so-called pictures of health contribute to many men’s poor body image, which in turn can lead to eating disorders, muscle dysmorphia and steroid use. And besides, he says, “being shredded sucks”: the discipline required saps so much of life’s joy.

Changing your body won’t always produce the desired result. “I thought being thin would make me more confident, more attractive and more fun,” says Mr Dave Chawner, a comedian and author of the book Weight Expectations, about his recovery from anorexia. “It did the opposite.”

Do you choose the ways you exercise or move because they make you feel good, or because you don’t feel good enough in yourself? The philosophy of yoga, which teaches that we’re inherently whole and enough, helped Downs form a more positive relationship with exercise. There are, Jackson says, many good reasons to move that have nothing to do with appearance: improved longevity, quality of life, sleep, energy levels, posture. (OK, that last one is a bit to do with appearance.)

To be honest, I don’t always know whether I want to exercise because I’ll feel good if I do or because, out of some sense of obligation or concern for other people’s opinion, I’ll feel worse if I don’t. “Often, the reason we feel inadequate about our bodies is because we feel inadequate generally,” says Mycock. Meditation helps him to be mindful of how he’s feeling about his body and journaling to understand why he’s really feeling like that (as can therapy – see below). Knowing that can be a step towards changing it.

Contrary to the oft-spouted principle, pain is not a prerequisite for gain, says Mycock. And you’re not weak, as he once thought he was, if you get through leg day without throwing up or passing out. Athletes don’t push themselves to breaking point in the gym. You probably shouldn’t either.

The notion that we “should” be exercising or treating our bodies one certain, “right” way can, Downs says, add to pressure, reinforce self-criticism and make the many and varied alternatives open to us seem somehow less good. So, instead of what you should do, ask yourself what Downs does in order to remain creative and celebratory in his own movement practice: “What could you do?” Mr Jackson advocates enjoyable non-gym exercise or movement: hiking with friends, dance-partying with your kids, “couple’s acrobatics” in bed.

What would you say to a friend who was feeling guilty because they skipped a workout or deviated from their diet? Probably something nicer than you’d say to yourself. Compassion-focused therapy (CFT), which helped Downs to form a more positive relationship with his body, emphasises three “flows”: to others, from others and for ourselves. Noticing if your flows are imbalanced is the tributary to treating yourself as kindly as you would others.

One skipped workout or “nutritionally suboptimal” meal won’t cause you to miss your goals; getting injured or completely falling off the eating-well bandwagon might.

“Train like a child” isn’t a credo you’d necessarily expect from a former marine commando turned trainer to film stars. But as Mr Simon Waterson explains in his book Intelligent Fitness, it’s sustainable healthy. As adults, we rarely let ourselves do things just for fun, or stop when they’re not. And not every exercise session has to be structured or goal-oriented. Waterson would warm up Mr Daniel Craig partly by throwing a rugby ball around for half an hour, during which the trainer would assess his long-time client’s readiness – or unreadiness – to train and adjust the scheduled workout (a word that implies the opposite of play) accordingly. Sometimes, writes Waterson, a 30-minute kickabout might be more beneficial.

I have two daughters aged five and three respectively, and their utter unselfconsciousness in their bodies is so wonderfully pure that I want to protect it for as long as possible, and regain some for myself. They make me mindful not to be weird about food or disparaging about my body or anybody else’s. I’m also watchful for such behaviour by others. And I’m grateful for things my body can do, like pick my kids up and carry them on my shoulders, that it won’t always be able to.

Words have weight, even if you say them as a joke, or not out loud. If you criticise your body – yourself – enough times then, says Mycock, you’ll start to believe it.

By stealing an admiring glance at your body in the gym’s mirrors, all you’re doing, says Mycock, is creating dependence on that behaviour in order to feel good. Then on days where you’re not looking as big or lean, you’ll feel bad. Baggy gym clothes and headphones can help turn your thoughts to feeling rather than looking good, says Jackson, who warns that scales and “calorie burn” features can be unhelpful in that regard (not to mention inaccurate).

Self-esteem entirely founded on body image is, says Mycock, “like a pillar”. An injury, holiday or other obstacle to maintaining your physique can cause everything to come crashing down. Instead, he says, build out your other sources of worth – being a good friend, partner or parent, say, or your career, skills and interests, intellectual capacity, sense of humour, spirituality. (He keeps a list of accomplishments nothing to do with his body or the gym.) A wider base, “like a pyramid”, makes you less likely to wobble.

Professor Markey recommends aiming for “approach goals” (things you want to do) rather than “avoidance goals” (things you don’t). For example, aim to eat more nutritious food – say, one or two extra portions of fruit or veg a day – rather than never eat junk food. Some things are hard to always avoid, which will mean failure is too.

“Nutrition is a science, but eating shouldn’t be scientific,” says Ms Anne Richardson, a registered nutritional therapy practitioner qualified in eating disorders who shudders when she sees weekly meal preps on social media. We’re not machines with constant needs or desires day to day: eating should be more intuitive than obsessively weighing foods, scrutinising labels and organising your life around your diet. Removing pleasure from the equation can equal boredom plus bingeing on foods labelled as “forbidden”. She instead designates chocolate, ice cream and the like as “fun foods” to eat moderately in the knowledge that they’re not the most nutritionally valuable but are very yummy, rather than permanently avoided, which risks obsession and overconsumption.

“For any body, or lifestyle, to be considered healthy, there has to be balance,” Jackson says. When in Rome on tour with Muse, he’ll consume pasta, gelato, wine, cheese. And he won’t guilt-train to atone, but rather keep his body moving (gently) and get rest. Balance (like bodies) looks different for everyone: don’t, he says, miss out on life because you think you have to look a certain way before you can live it. Make memories. Get in the pool.

Pay attention to which TV shows, magazines, sites or social accounts make you feel bad about your appearance, then don’t pay them any more attention. What body image experts call “protective filtering” – avoiding negative influences – doesn’t, says Professor Markey, just apply to the media. But media provides almost limitless scope to compare ourselves to others – a tendency that psychologists think is natural but, thanks to modern technology, can now occur on an unnaturally large scale and constantly.

This benchmarking process of “social comparison” happens more with “like peers”, who we less easily dismiss as unrealistic ideals than celebrities or models. Social media, which blurs the lines between celebs and peers, can therefore be especially harmful. But as well as unique challenges, social also, says Professor Markey, presents opportunities for protective curation. Rather than unfeasibly shredded fitness influencers, you could, say, follow body positive campaigners (#bopo), experts like those mentioned herein. Or just more people who wear shirts.

When looking at celebrities, models and influencers, keep in mind that, like Derek Zoolander, they’re professionally good looking. Not to overlook their hard work. But they benefit significantly from what I think of as “body privilege”, including good genes and hired help: PTs, personal chefs, photo editors, sometimes even surreptitious CGI airbrushing. When people ask if they, too, can look like James Bond or Captain America, Mr Waterson replies that yes, it’s possible – if they have his advice and his clients’ dedication and genetic potential. It might however be more beneficial, he writes, to not try and replicate his clients, but use them as inspiration to become the best version of yourself. The only way to actually get a body like Mr Brad Pitt in Fight Club, as I so ardently yearned aged 16, is to get a time machine, travel back and be born to Ma and Pa Pitt.

“It’s easy to compare yourself to other people and wish you had a body like them,” says Chawner. “But you know what? You‘re not them. Stop trying to get someone else’s body and enjoy yours.”

When Professor Markey has a bad body image day – which happens, even to experts – she comes back to one of her mantras: “I’m a middle-aged woman, professor, wife, mother of two teenagers – and I’m doing OK. No one I really care about cares much about how I look.” Formulate your own affirmation that emphasises self-acceptance. Cleave to it.

One of Downs’ mantras is “you don’t have to stay where you started just because you started there”. Familiarity is comforting, he says, and changing your goals, and what you do to try and reach them, can feel like failing. But stopping something that isn’t working and looking for another way is in fact a form of resilience. You may, says Jackson, find that a different form of exercise makes you feel good about your body, not down on it.

Having struggled with an eating disorder, Downs spent much of his twenties trying to catch up on all the fitness goals he felt he’d missed, which led to burnout and a lack of awareness of how his own body worked. Make your movement and exercise work for you, he says, instead of following somebody else’s idealised regimen. Learn to listen to your body, says Jackson, trust it and meet its needs as they arise.

Insecurity sells, especially about sex. (Hence all the ads for penis enlargement lotions, potions and operations.) The fitness industry, like many others, capitalises on inadequacy – the “extreme aesthetic” it promulgates is, says Jackson, “a tool for selling products and getting likes”. Too-good-to-be-true workout plans and supplements, especially accompanied by messages about body dissatisfaction, are “red flags”.

If you feel your body image concerns are serious, then, says Professor Markey, you should get professional, specialist help. Charities such as the National Eating Disorders Association in the US, Beat Eating Disorders in the UK and the Butterfly Foundation in Australia are good places to look. Therapy hasn’t made Mycock immune from ever feeling bad about his body, but it has helped him understand and be honest with himself.

Both the external pressure and internal criticism we all feel about ourselves is exhausting. Which is why taking a “body neutral” stance – basically not having to hate your body or love it – can provide respite. “I don’t like the body-positivity mantra that you should ‘always love your body’ because that’s yet another unrealistic body expectation,” Chawner says. “There are going to be times when you don’t wholly love the way you look, and that’s normal.” Like your body instead.