The first sports drink was Gatorade, an elixir filled with sugars and salts that was developed in 1965 to prevent dehydration in football players at the University of Florida. The initial 1996 American College of Sports Medicineguidelines for fluid replacement held that endurance athletes should concentrate on aggressively replacing “all the water lost through sweating.” Gatorade and its rivals market their drinks for this purpose, and by 2015, their sales exceeded $8.4 billion per year (Gatorade, a PepsiCo product, accounted for nearly 30 percent).

But sports drinks generally help only people who exercise for more than an hour, and the benefit comes mainly from the sugars, not the fluids, particularly if the carbohydrate is a mixed dose of fructose and glucose.

Severe dehydration can imperil athletes, but according to studies by South African researcher Timothy Noakes, the author of “Waterlogged: The Serious Problem of Overhydration in Endurance Sports,” the body is more than equipped to tolerate mild dehydration, while overhydration may pose more severe risks.

In several high-profile cases, overdosing on liquids has led to dangerous and occasionally fatal outcomes. As a consequence, the 2007 American College of Sports Medicine position recommended a more cautious approach: People who exercise for long periods should avoid losing more than 2 percent of their body mass, and within that very broad parameter, fluids containing carbohydrates can be helpful during longer endurance activities.

Still, all sports drinks have calories, and consuming them when water will suffice can contribute to fat gain.

Popular magazines and websites suggest that a six-pack is just a few maneuvers away. Shape magazine calls planking the “secret to amazing abs.” And Health magazine says you can eliminate your “muffin top” with “fat-burning ab exercises,” such as crunches and “donkey kickbacks.”

Fat is generally categorized as subcutaneous (under the skin) or visceral (around organs); love handles are the former kind. Fat stores are burned from all areas evenly when you eat less and exercise more.

A six-pack does not emerge when you target the fat in your abdominal area; it comes from bulking up those muscles, which can grow strong enough to show through the layer of subcutaneous fat — they simply appear more pronounced with a lower percentage of overall body fat.

As it happens, women tend to maintain fat around the hips and upper thighs, while men keep it around the lower abdomen. An exercise regimen that burns off body fat generally will help slim down all areas, including the subcutaneous and visceral abdominal regions, narrowing the waist and flattening the belly.

Weightlifters, Instagram celebrities and commercial purveyors say these concoctions are what you need to add muscle mass. Men’s Fitness instructs that whey and casein “enhance muscle-building.” Hafthor Bjornsson, the weightlifter who plays the Mountain on “Game of Thrones,” volunteered that he takes branched-chain amino acid and glutamine supplements.

Yes, you need to consume more protein than your muscles degrade, but the optimal intake for resistance training varies based on your diet, your metabolism and your training.

According to a study I conducted in the late 1980s, the amount of mixed protein needed by very-well-trained weightlifters is only about 50 percent above that needed by sedentary folks.

Varsity-level strength athletes training six days a week and weightlifters during the early stages of a very intensive program need, at most, 100 percent above the requirements for sedentary people. Taking protein beyond these amounts leads to an increase in protein oxidation (you just pee out the extra nitrogen) with no increase in muscle protein synthesis.

Powders are simply unnecessary, since food more than suffices. The current recommendations of the American Dietetic Association, Dietitians of Canada and the American College of Sports Medicine can be met with a proper diet, in which proteins with high biological value (egg whites and milk) are pound for pound better than meat and fish, which themselves are better than plant-based proteins such as soy.

Most government and professional fitness guidelines emphasize aerobic programs, such as jogging or cycling. Canada, for instance, suggests that adults age 18 to 64 “focus on moderate to vigorous aerobic activity” for “at least 2.5 hours a week.” The American Heart Association emphasizes aerobic exercise for “overall cardiovascular health,” or a combination of more vigorous aerobic activity plus “muscle-strengthening activity.”

But recent evidence suggests that shorter bouts of high-intensity interval training (HIIT) — which forces a different kind of oxygen-free energy creation inside the muscles — can provide similar benefits to longer moderate-intensity continuous (MICT) workouts, in about one-fifth the time.

“The One Minute Workout,” by kinesiologist Martin Gibala, documents the research into these fairly new form of exercise, which can include burpees and cycling sprints. Work that I have been involved in with his group has shown that the muscle mitochondria (the powerhouse of the cells), maximal aerobic power, and even body fat and glucose improvements are identical between HIIT and MICT. What’s more, high-intensity workouts are safe and effective for people with obesity, diabetes, heart disease and cancer.

At the end of the day, there are many ways to attain the same fitness goals. It is important to choose the type of exercise that works for you.

The Marist poll regularly finds that weight loss is the top New Year’s resolution among its respondents, followed by exercise. (Physicians also say weight gain is one of the major problems they see during the holiday season.) Forbes says “exercise is critical in the maintenance phase, which is well known to be more difficult than the weight loss phase.” And even WebMD hosts the stories of people who credit exercise for their lost pounds.

The two major components of body weight are body fat and lean body mass (muscle and bone). Several studies have clearly shown that, while endurance and HIIT exercise can reduce visceral fat (lower waist circumference) and improve cardiovascular fitness, they often do not result in overall weight loss.

Often, athletes find significant strength improvements with resistance exercise but no change, or even an increase, in total body weight. A 2012 study in the Journal of Applied Physiology followed individuals who worked out for eight months and saw no weight loss (despite other significant health benefits).

The most effective way to knock off weight is by combining exercise with dietary and lifestyle changes — and to focus on the many health benefits of working out without becoming a slave to the scale.

Mark Tarnopolsky is Professor of pediatrics and director of the Neuromuscular and Neurometabolic Clinic. This post appeared in the Washington Post.