Men: Here's How to Eat and Exercise to Lose That Pool T-Shirt

In September 2015, Vernon Gudger's doctor gave him terrifying news: His blood sugar levels were so high, he was on the cusp of being prediabetic.

Gudger's father had died of complications from diabetes after having both his legs amputated above the knees because of the disease. Gudger, 52 at the time, was 5-foot-9 and weighed 197 pounds. His physician told him he had to lose weight or he'd likely become diabetic.

It was a month after Gudger had retired as a sergeant from the Metropolitan Police Department in the District of Columbia. He went back to work -- on himself. "I decided to cut out all the sugars and the carbs," Gudger says. No more McDonald's French fries. So long cookies. Bye-bye bread. The ex-cop began eating oatmeal with blueberries, blackberries or banana slices for breakfast. Lots of fresh fruits, vegetables and lean poultry, and fish for lunch and dinner. He made sandwiches substituting large portabella mushrooms for bread slices. Gudger took to exercise with the same zeal with which he once patrolled city streets, going to the gym every day, lifting weights, doing bench presses and riding a stationary bike. He brought home the base of a tree he found at a construction site and held the wood, which weighs about 40 pounds, on his shoulders behind his back as he executed squats in his apartment.

[See: How to Be the New Kid in Fitness Class.]

The fitness regimen worked. Four months after his doctor's appointment, he had dropped 25 pounds, weighing in at 172. Gudger has maintained his fitness regimen, and in April, he was a cut 165 pounds. "I feel good," Gudger, now 54, says. "Before, I didn't want to take my shirt off at the pool or at the beach, I didn't want my stomach to be seen. Now, I can't wait to go to the beach."

Not every man will have the time the retired Gudger has to work out, or the stark motivation provided by his family history of diabetes. (In addition to his father, his grandparents on his father's side both had their arms and legs amputated because of their diabetes.) But there are some basic changes men can make starting now to get in better shape for the summer and feel better about taking their shirt off at the pool or beach. "If you want to be fit, healthy and stave off as many chronic diseases as you can, keeping weight off after you've lost it is foundational," says Lise Gloede, a registered dietitian based in Arlington, Virginia. "We must accomplish this in steps, with reasonable goals."

Whether your objective is to look good in swimming trunks, to lose weight to cut down your odds of developing diabetes, heart disease or other weight-related conditions or simply to improve your overall health, here are some diet and exercise changes you can start now to achieve your goals by summer:

Don't just eat less -- change your dietary habits. "I didn't diet," Gudger says. "You have to change your dietary habits. There's a big difference." Gudger has nothing against specific healthy eating regimens, such as the DASH diet or Mediterranean diet. Rather, eating less of the same unhealthy foods, which some people consider dieting, would not have worked for him, Gudger says. By eating more nutritional food, Gudger says, he feels full and has more energy than when he ate junk food. "I can go for a whole day eating fruit and not feel hungry, even when I work out."

[See: 8 Morning and Nighttime Rituals Health Pros Swear By.]

Always eat breakfast. It's important to start your day with a healthy breakfast, whether it's a cup of oatmeal with fresh fruit, a hard-boiled egg with a whole-wheat English muffin or a cup of yogurt, Gloede says. A good breakfast provides energy for the day and improves mental concentration. Research suggests that people who eat breakfast tend to weigh less than those who skip it, perhaps because individuals who don't eat that meal consume more at lunch and throughout the day.

Develop a strategy for barbecues. Outdoor cookouts could momentarily bust your healthy eating regimen, but they don't have to, says Erin Clifford, a wellness coach in Chicago. It's possible to eat a healthy barbecue meal without feeling like you're missing out. She suggests picking one food to splurge on -- such as a dessert like pie or a dish like macaroni salad -- and loading the rest of your plate with vegetables and fresh fruit. If you want a hamburger, eat it without a bun. "You won't feel deprived," Clifford says.

Lift weights or do resistance training. It's a fallacy that we can transform fat into muscle, says Dan Gaz, a wellness exercise specialist with the Mayo Clinic's healthy living program in Rochester, Minnesota. "Fat and muscle are two completely different things," Gaz says. "We can't change one into the other, but we can change the proportionality." Lifting weights can help change your shape, Gaz says. You needn't lift like an aspiring bodybuilder -- starting out with moderately difficult resistance is fine, so long as you keep pushing yourself by incrementally lifting more weight or adding more repetitions. You don't want to stay in a routine that's comfortable. "Say you're doing three sets of 10 reps of bench presses at 100 pounds," Gaz says. "If that gets easy, try three sets of 10 at 105 pounds, or four sets of 10 of 100 pounds." You may not need to join a gym or buy weightlifting equipment; some public parks, such as an assortment in Los Angeles County, have adult fitness areas with exercise equipment. And you don't need any equipment to do push-ups, planks, squats or lunges.

Eat and exercise strategically. To build muscle and get trimmer, your body has to synthesize protein, says Jenna Bell, a registered dietitian based in St. Petersburg, Florida. Typically, people should eat about .8 of a gram of protein for each pound they weigh, in 20-gram increments throughout the day, Bell says. Protein shakes and Greek yogurt are good sources of protein that can fuel workouts for maximum effectiveness. "You want to have enough energy to fuel your workout," Bell says. "The food you eat after your exercise will help synthesize the protein so you can reap the benefits by building lean muscle. Think of your foods as having function." Cottage cheese, whey protein shakes, lean meat and peanut butter and jelly sandwiches on whole-grain bread are good post-workout foods.

[See: The 10 Best Diets for Healthy Eating.]

Moderate your alcohol intake. Lots of guys like to relax with a couple beers or other drinks after work or while watching a game, but that alcohol consumption adds calories. For instance, 12 ounces of beer contains an average 153 calories, while a 5-ounce glass of red wine has about 125 calories and a 1.5 ounce serving of gin, rum, vodka, whiskey or tequila typically contains 97 calories, according to the National Institutes of Health. These are empty calories with no nutritional value that can lead to body fat, usually in the stomach, Bell says. Instead of two beers, have one. "Try manageable changes," she says.

Ruben Castaneda is a Health & Wellness reporter at U.S. News. He previously covered the crime beat in Washington, D.C. and state and federal courts in suburban Maryland, and he's the author of the book "S Street Rising: Crack, Murder and Redemption in D.C." You can follow him on Twitter, connect with him at LinkedIn or email him at rcastaneda@usnews.com.