Summer is fast approaching, leaving you little time to achieve beach-body perfection. But sports scientist and author Venice Fulton warns that a restrictive diet promising rapid weight loss isn’t the answer. “People need a diet that will preserve long-term health and the only way we can do that is by making them experts in understanding how food and their life interact,” he says.

Combining nutrition, biochemistry, genetics and psychology, Six Weeks to OMG promises you’ll shed the pounds. Curious, we asked nutritionist Dr. Carson Liu to weigh in on the plan.

Sleep in

Big sleepers are slimmer and generally healthier than those that survive on little sleep. You must wake up refreshed, claims Fulton. “Deep sleep lets the thyroid reset itself and get to full speed once you wake. When your thyroid is high, your metabolism at full pace.”

What the doctor says: Yes! Sleep also helps keep stress hormones down: they are released from the adrenal glands.

Skip breakfast

Eating a morning meal around 10 a.m., instead of breakfast increases fat burn: “Skipping breakfast allows you to burn off excess body fat as it’s the one time in the day your system is running on empty and moving around,” Fulton says. Ideally, you should eat three hours after you wake.

What the doctor says: No way! Eating breakfast helps you lose weight and prevents you from binge-eating at dinner.

Go skinny-dipping

Take a 15-minute cold bath in the morning. “Cold water makes the body panic, shifting your metabolic rate into overdrive as heat production is increased in order to protect the core organs,” says Fulton.

What the doctor says: Yes! Exposing the body to cold temperatures does increase metabolic rate.

Drink black coffee

Caffeine promotes weight loss by boosting the central nervous system by stimulating the fight or flight response using adrenaline. This forces fat cells to empty their contents into the blood and these free fatty acids are then transported to your muscles and used as fuel. This only works if you’re drinking on the go, warns Fulton.

What the doctor says: Yes! The caffeine in coffee increases metabolic rate and suppresses appetite. As a diuretic, coffee will also cause you to lose water weight.

Focus on satiety

We tend to overeat carbs when we should be having no more than a 40-gram portion with each meal. Size-wise, that’s the equivalent to a stack of four iPhones. Protein (any source) should take up half. Just don’t restrict yourself. “When you restrict something from your diet, the more obsessively you will focus on it,” adds Fulton.

What the doctor says: Yes! Cutting a certain food from our diet will only make us crave it.