Max Lowery, 27, recently told us why he would never touch a protein shake, even if you paid him.
1. You should stretch before a workout.
It's possibly controversial, but Lowery insists that static stretching before a workout can do more harm than good and make your muscles less efficient for your workout.
Static stretches should be done at the end of your workout, when your muscles are already warm, while your warm-up ideally should consist of dynamic movements, activation, and mobility.
Below is an example of one of Lowery's favourite dynamic warm-ups, which he said is ideal for kicking off your workout. He says he always warms up for 25 minutes before a hardcore session.
2. The more exercise you do, the better.
"This mentality can lead to all sorts of problems," he said. "People don't realise that in order for your body to adapt to any exercise stimulus you need to have adequate recovery."
Your rest days are just important as your training days, according to Lowery, especially if you are doing high-intensity interval training, or HIIT, which challenges the nervous system.
This can end up stressing your body out even more, which can lead to weight gain, insomnia, and damage to the immune system, he said.
Lowery recommends three to four good sessions in the gym a week.
"This is more than enough," he said. "All the while, you should be walking, moving, stretching as much as possible."
3. You should do cardio for weight loss.
"The No. 1 factor in losing weight is your diet," Lowery said. This is something several high-profile personal trainers have echoed, including Justin Gelband, who trains Victoria's Secret models. He told Business Insider that "85% percent of what you do is what you eat."
Lowery added: "That being said, exercise should be used to complement a good diet. Cardio (aerobic exercise) is great for health reasons, and you will burn calories while doing it. But your biggest concern when you're trying to lose weight is muscle loss."
He said that if you lost fat and muscle along with it, you would make it harder to keep the weight off in the long run. That's because the more muscle you have, the higher your metabolism is.
Instead, he says anaerobic activities, such as weight training and sprinting, are the most effective for building lean muscle mass, which will increase your metabolism and decrease fat.
4. And crunches for a 6-pack.
Yes, you heard right: Countless stomach crunches won't necessarily get you ripped, according to Lowery.
"The biggest factor in getting a six-pack is having a low-enough body-fat percentage so that you can actually see your abs," he said. "Everyone has abdominal muscles, but if you have a layer of fat above them, you will never see them."
Lowery's theory is backed up by science. A recent study found that it's not possible to target specific areas of the body for fat loss.
In an experiment with two groups of adults, while one group did targeted ab exercises five days a week for six weeks, the other focused on keeping a balanced "isocaloric diet." The researchers found that the crunches alone did not have a significant impact on abdominal fat or other measures of body composition.
"The only way to decrease body fat is to make changes to your diet," Lowery said. "Once your body-fat percentage is low enough, whilst crunches and sit-ups may serve a purpose for activating your abdominal region, they are not very good for hypertrophy."
To build your abdominal muscles, you must train them the same way you would any other muscle. Start to add some weight into the mix, and use compound movements like squats, deadlifts, and pull-ups that take a lot of abdominal activation.
Here's one of Lowery's "ab activation" sequences:
5. You have to 'destroy' yourself.
With the huge rise in popularity of HIIT classes, particularly in London, many have adopted the mindset that a workout is useless unless you feel "destroyed" at the end.
But Lowery is among numerous personal trainers who have concerns about the short- and long-term effects on people who are not used to such high-intensity training -- particularly those who sit at a desk all day -- overexerting themselves at the gym.
Potential side effects from overtraining include weight gain, insomnia, and illness.
"There's a time and a place for pushing yourself really hard in a workout, but issues can arise when this happens in every session," Lowery said. "Sometimes your body will react badly to extra stress -- if you haven't slept enough the night before, if you haven't eaten the right food all day, or if you are generally feeling stressed out at work.
"For the days where you don't feel 100%, you should do something much less strenuous -- a brisk walk, a slow jog, swimming, or a stretching session would be much more beneficial, and it would mean you're less likely to overtrain."
This post originally appeared on Business Insider.