You’ve been dutifully training your client for 4 months. He’s stronger, but his oversized belly has not budged. You suspect that what he really needs is a diet overhaul—but you’re a certified fitness professional, not a nutritionist. Still, you might be able to steer him toward more weight and fat loss if you could just give him a tip or two about what to eat . . . but should you?

It depends.

Doling out dietary advice is tricky. On the one hand, what’s the harm in suggesting that a person eat more vegetables? On the other hand, at what point is specific dietary advice beyond your expertise? Even though recommending that a client cut out gluten or try an amino acid supplement might seem safe, if your nutrition advice were to hurt someone, you could be sued.

At the same time, food and fitness are inevitably intertwined: what and how much a client eats impacts health, weight management and fitness performance. “Fitness professionals should talk about nutrition, but they should stick with giving general, nonmedical information,” says Laura Kruskall, PhD, RD, FACSM, director of nutrition sciences at the University of Las Vegas in Nevada and author of Fitness Professionals’ Guide to Sports Nutrition and Weight Management (Coaches Choice 2010). A trainer’s ongoing contact with clients presents a lot of teachable moments, agrees Kristine Clark, PhD, RD, FACSM, sports nutritionist and director of sports nutrition at Pennsylvania State University. “So trainers should address nutrition, but they should be mindful of not misinterpreting scientific information.”

An effective way to educate clients and help them improve their dietary behaviors is to use a food log, also known as a food journal, food record or diet diary. “All of our clients use food logs because they keep [them] accountable and prevent mindless eating,” says Edwina Richards, a personal trainer at Live Well Fitness Center in Muncy, Pennsylvania. Here are tips on how to use this tool—and how to do so safely.

What Is a Food Log?

A food log is a record of all foods and drinks consumed within a specified period of time. Food intake is typically tracked for 1 to, ideally, 7 days. Since patterns can differ between the weekend and the workweek, the more days that are tracked, the better.

At its most basic, a log lists the type and amount of every food and drink item consumed. The log can be written on a piece of paper or preprinted blank form, typed into an online nutrition website (such as href=””> or entered into a smart phone (iPhone apps are available).

Precision is key for accuracy. Ideally, clients should enter what they eat when they eat it (rather than relying on memory later). They must be taught how to estimate portions (a 3-ounce serving of meat is about the size of a deck of cards, for example). All ingredients in meals should be detailed (“2 cups of mesclun lettuce, one-half avocado and 1 tablespoon olive oil”). Some “guesstimation” may be required for restaurant meals for which recipes are unknown. Brand names of packaged foods should be included.

The more information is recorded, the more helpful a food log can be. Keeping track of when they eat will help clients highlight patterns such as skipping meals. Including what they were doing when eating, and who they were with, can reveal eating triggers. “One client noticed that whenever she cheated by eating high-fat snacks, she was with her husband. So we motivated him, and now they make healthier choices when snacking together,” says Fay Lougheed, a personal trainer in Shuswap, British Columbia.

Including the time, type and duration of workouts along with mealtimes can reveal whether clients are fueling workouts sufficiently. Tracking feelings associated with eating can also help improve behaviors. “I have clients rate their hunger level and emotions at the time of eating. Often, they see an association between feeling anxious, bored or tired and what and when they eat,” says Diane Buchta, personal trainer and owner of Tri Fitness in Del Mar, California.

How Can You Analyze a Food Log?

“Evaluating food diaries is part of the extensive nutrition assessment process, and in some states this is an illegal procedure if you are not licensed or certified to do [it],” explains Kruskall. Of course, that doesn’t mean that you can’t still get a general overview of dietary patterns. Just know how far you should go in commenting on the information (see the sidebar “How Nutrition-Savvy Are You . . . Really?”).

Also realize that you probably don’t have the complete picture. “Unless the client is obsessive and trained to estimate portions precisely, the journal will not be as accurate as you think,” says Clark. Calorie counts may be off, and specific nutrient amounts may be unreliable. So be wary of assuming that someone is deficient in a certain vitamin or mineral.

You can get a picture of your clients’ energy balance status by comparing how many calories they eat with how many they burn (see the sidebar “Sample Food Log”). Online food logs usually calculate calories, but you can do it yourself using the U.S. Department of Agriculture (USDA) nutrient database ( or websites such as Asking clients to log serving size and calorie information from Nutrition Facts labels can be helpful. Some chain restaurants provide nutrition information on company websites. Avoid getting too nitpicky about the numbers, because calorie counts are never exact unless you are measuring food and metabolism in a lab.

Be aware that the longer that meals are tracked, the healthier food choices tend to become. This is one reason why weight loss programs like Weight Watchers® encourage self-monitoring. When we spotlight our habits, they tend to improve. So, there’s a good chance that simply including this practice will automatically improve how your clients eat, regardless of your technical input. “One client taped the wrapper from her last candy bar to a page in her journal as a reminder of how horrible she felt after eating it. She’s now down 30 pounds, and her doctor took her off of her blood pressure and cholesterol medication,” says Richards.

What Kind of Nutrition Advice Can You Give?

So, what can you say, and are there areas where you dare not tread?

Nutrition counseling involves relaying factual information about foods and nutrients; explaining the science or mechanisms behind aspects of nutrition; showing clients how to modify unhealthy eating behaviors and make nutritious food choices; and prescribing dietary changes and/or supplementation that may help treat a health condition. Trained nutritionists and dietitians have an extensive educational background in the biochemistry and physiology of nutrition, drug-nutrient interactions and medical nutrition therapy. A personal trainer with only a cursory knowledge of nutrition, gleaned from magazine or website articles or a short course in nutrition, is not well qualified to give in-depth nutrition advice.

Yet it is not uncommon for trainers with an incomplete understanding of the scientific rationale to jump on the diet trend of the day, advising clients to follow a fad diet book, to cut carbs or avoid fruit, to swear off processed sugar or high-fructose corn syrup or to “detox” with special juices or supplements. “Some people make pseudoscience sound like real science, and it takes an in-depth understanding of nutrition sciences to tell those things apart,” says Karen Reznik Dolins, EdD, RD, CSSD, CDN, nutrition professor at Columbia University in New York City and sports dietitian for the Columbia athletics department. “Someone who lacks that knowledge will embrace something they read in a book that sounds like it makes sense without realizing that they are passing along misinterpreted information.”

While dietary supplements are assumed to be safe since they are not regulated by the U.S. Food and Drug Administration, it is a bit of a crapshoot whether a person needs them, whether they work and, if so, which doses are safe for different individuals. So recommending supplements, especially as a treatment or cure for specific symptoms that your client may describe, is a murky no-go area (Perko & Dennison 2000).

“It’s safe to discuss nutrition information that has been confirmed by a scientific body—such as the USDA Dietary Guidelines or the American Dietetic Association (ADA)—and that is in the public domain,” says Clark.

So information based on the USDA Dietary Guidelines or contained in ADA or American College of Sports Medicine (ACSM) position statements, is fair game (see “Resources”). Encouraging evidence-based healthy eating patterns and giving ideas on how to better meet recognized nutrition guidelines, such as increasing fiber intake or meeting fruit and vegetable quotas, are acceptable practices. And helping clients spot poor choices (too much junk food) or unhealthful behaviors (excessive drinking) is also okay. “I try to coax my clients into looking at their food choices in a healthier way,” says Buchta. “Once they realize that how they eat is not balanced or inclusive of all that they need, I’ve seen people go from eating as few as only one fruit or vegetable per day to eating six to eight in a matter of weeks.”