I've spent almost 30 years studying how food and lifestyle choices affect the metabolism. The truth is, there's a lot we can do to boost metabolism. In fact, we can get better as we age—through our 30s, 40s, and well beyond our 50s!

With a fast metabolism, you can easily maintain a healthy weight, burn fat, and enjoy feeling confident and strong by building and maintaining youthful muscle. You also experience sharper mental focus and sustained energy throughout the day without that dreaded afternoon crash that sends people lining up for a cup of joe to get through the p.m. hours.

Unfortunately, many of my clients don't show up in the above condition. More likely, they are suffering from a sluggish metabolism.

Here are some of the classic signs of a slow metabolism; then I'll share my pro tips for revving your metabolism for faster weight loss, sharper mental focus, and amazing energy so you're at your best, no matter what age.

Let's first go over signature signs of a slow metabolism. See if you can relate to any of these:

With a slow metabolism, stubborn weight gain shows up—especially around the middle. You'll find that even the go-to workout routines and diets that worked in the past seem to have zero impact. This is such a prevalent condition, I've coined the term "weight loss resistance" to describe it. The good news is that there is actually a LOT you can do to turn this around (but more on that later).

Are Tums or Rolaids on your daily after-dinner menu to head off the embarrassing and uncomfortable gas and bloating that take over after every meal? You're not alone! Up to 70 million Americans suffer from some form of digestive issue, including heartburn, leaky gut, poor digestion, and malabsorption. This can lead to body aches, nutrient deficiencies, fatigue, inflammation, and a slow metabolism.

When your metabolism is slacking off, hormones can also get out of balance. You end up with dry, scaly skin and thinning hair. Check your mirror to see if you are thinning at the crown or if the ends of your eyebrows are getting sparse. Having trouble staying warm, especially in your extremities? You guessed it—that's another signal from your body that your metabolism could use a makeover.

Signs of blood sugar imbalance include carb cravings and the urge to eat every few hours. Otherwise, you risk getting "hangry" and snapping at everyone around you as you storm your way toward that bag of chips or plate of cookies. After the sugar high bottoms out, you're left with the backlash of low energy, brain fog, and the overwhelming need to take a nap at your desk around 3 p.m.

If any of the above sounds familiar, don't worry because I've got some answers for you!

Your body is not a bank account; it's a chemistry lab. In terms of weight loss, it's not just about calories in and calories out. The foods you eat and your lifestyle choices send signals to your body that tell it to either thrive or break down. It sounds daunting, but actually, this is great news because once you know what to do, you can take control and reset your metabolism. Here are some tips that will tell your metabolism to wake up and get moving:

Avoid the kitchen after dinner to create a 12- to 14-hour overnight fast. This will prepare your body to burn fat the next morning. Eating one to two hours after waking up will help you prevent a blood sugar roller coaster and the resulting energy and mood swings. Also, if you nix snacking between meals and eat every four to six hours, you avoid spiking your insulin constantly and allow your body to dip into your fat stores for energy. To keep cravings at bay, make sure you have lean, clean protein; healthy fats; and fiber at every meal. Grab a copy of my New York Times bestselling book, The Sugar Impact Diet, to get my three-step process to shift from a sugar burner to a fat burner!

I wrote another NY Times bestseller all about food intolerances, The Virgin Diet, and it explains why they play such a huge part of reversing weight-loss resistance. Food intolerances cause a cascade of health issues, including leaky gut, immune reactions, and chronic inflammation, which affect metabolism. By removing the biggest culprits—including gluten, dairy, soy, eggs, corn, peanuts, and sweeteners—my clients typically lose up to 7 pounds in the first seven days!

Staying hydrated has been shown1 to increase metabolism by as much as 30%. Conversely, just 2% dehydration can cause2 exercise performance to suffer, impair your alertness, create an inability to focus, and encourage signs of fatigue. So make sure you're sipping water throughout the day. The only time to slow down or avoid water is when dining so you don't dilute digestive enzymes that break down food for absorption.

Say goodbye to all those hours on the treadmill. Endurance exercises like long-distance running actually cause your body to break down (think muscle loss!), stress your immune system, and may even cause weight gain. To get your body into fat-burning mode and kick up your metabolism, try burst training, otherwise known as high-intensity interval training (HIIT). When you do this first thing in the morning, it causes an oxygen deficit that your body needs to make up during the day, which will cause greater fat loss3.

Stress is an unavoidable part of life, but when it becomes chronic, your stress hormone, cortisol, starts to work against you by breaking down muscle, storing fat, and causing insulin resistance4. To boost your metabolism, make de-stressing a priority: Meditate, pencil in time with a bestie, or indulge in a relaxing bath with lavender essential oil and candles.

Make sure you get seven to nine hours of uninterrupted sleep every night. This will boost your human growth hormone (hello, fat burn) and quiet your hunger hormones. Studies show5 that sleep deprivation can prevent weight loss, even if you follow a great diet, so don't sabotage all of your hard work by burning the midnight oil. In fact, just one night of sleep deprivation can affect your metabolism, resulting in weight gain and blood sugar issues.

Now, it's your turn! Follow these tips to boost your metabolism, become a fat burner, and set yourself up to be in the best shape of your life at any age.