The Right (& Wrong) Ways to Lose Weight

woman strength training

Remember: cardio and strength training are both important parts of your exercise regimen.

Exercise is medicine. This is a key message that’s worth reminding everyone of. Given that two-thirds of Americans are either overweight or obese, and that healthcare costs (to say nothing of quality-of-life costs) are staggering, we need to figure out how to turn this ship around. Here are eight truths about diet and exercise that anyone trying to lose weight (or even maintain weight) and stay fit should know:

1) Miracle slim-down diets (aka “crash diets”) do not work. Is it true the less you eat, the more weight you will lose? No. A big slashing of calories poorly predicts how much weight you will lose because your body adapts to perceived “famine” conditions by conserving energy.

close up of broccoli

The secret to weight loss: a healthy diet rich in fruits and vegetables (like broccoli), whole grains, legumes, healthy fats (like olive oil), and lean meat and dairy (if you eat dairy).

In a three-month study, young, healthy women were given a diet to lose weight. One diet had a moderate (-400) calorie deficit; this group lost six pounds in 3 months. The other diet had a severe (-850) calorie deficit; that group lost only 8 pounds. This was far less than predicted and related to a drop in resting metabolic rate. The body’s ability to conserve energy is quite powerful! If you want to lose weight, plan to chip off just a few hundred calories at the end of the day, rather than starve yourself by under eating all day.

In fact, men who want to lose weight should not crash diet, either. They will lose not only muscle but also testosterone (a muscle-building hormone). In a three-week study, soldiers ate a high-protein diet (3 x the RDA; 2.4 g pro/kg/day) but under ate calories by 40% below the amount needed to maintain weight. While the very high-protein intake helped counter loss of muscle, it did not maintain testosterone levels. Remember: chipping off a few hundred calories is preferable to a chopping off a thousand. Two fewer cans of soda or beer a day can make a difference in weight!

2) It doesn’t matter how often you eat; what matters is calories. Are dieters better off eating three small meals plus three small snacks—or eating the same amount of calories but in just two meals? For two weeks, obese middle-age women ate calorie-controlled packets of food either two or six times a day. Either way, the subjects reported being hungry. Eating six smaller meals did not appear to improve appetite response. So take your choice how often you want to eat, being sure to keep the total calories within your daily calorie budget.

Cup of coffee

Coffee has many health benefits—thanks to its antioxidants—but weight loss is not one of them.

3) No, coffee can’t curb your appetite (sorry!). Many dieters drink coffee for breakfast, swearing it curbs their morning hunger pangs. Yet, a study with 12 subjects reported no differences in appetite (and subsequent food intake) when their breakfast and mid-morning beverages were 1) water, 2) water+caffeine, 3) decaffeinated coffee or 4) decaf+caffeine. At lunch (4.5 hours after breakfast), the subjects reported similar amounts of hunger and ate similar amount of calories, regardless of their caffeine intake. The coffee did not effectively curb their appetites.

4) Listen to your body. What happens to food intake when healthy college men who exercise regularly are told to sit for 10 additional hours a week for 8 weeks?  They naturally eat less! At baseline, the subjects ate about 2,600 calories a day (47% carb, 18% protein, 32% fat). When they were told to be more sedentary, they intuitively ate less than baseline. They chose the same foods, just smaller portions. Only 1 of the 8 subjects ate more than at baseline. The moral of the study: If you get injured and cannot exercise, your body can naturally desire fewer calories. The trick is to listen to your body’s cues.

5) Regular exercise does more than just keep you fit. Exercise can impact not only weight but also the kinds of microbes that grow in the gut. In mice, the kinds of microbes differ by 40% between sedentary lean and obese mice. Even mice made obese by a high-fat diet—but allowed to use an exercise wheel—had a lean phenotype compared to the sedentary obese mice with no access to the exercise wheel. The exercised mice had distinctly different gut microbes. We need more research to understand how exercise impacts gut microbes in humans and how those microbes impact metabolism and weight.


Lifting weights boosts bone density and your resting metabolism (which is key to how many calories you burn a day).

6) You’ve got to lift weights. Female athletes commonly have low bone mineral density. Is this related to their being light in weight? Having low body fat? Less muscle? A study of 44 female D-1 athletes (from cross-country, tennis, basketball, and soccer teams) suggests that bone mineral density significantly relates to muscle mass. The more muscle, the better the bone density. Keep lifting those weights!

7) Any exercise is better than no exercise. Does very slow walking (1 mile/hour) on a treadmill desk offer any health benefits? Yes. In a study, 32 college students consumed 300 calories of glucose and then either 1) remained sedentary for two hours or 2) for two hours, alternated walking on a treadmill workstation for 30 minutes then sitting for 30 minutes. The results suggest even very slow walking helped with blood glucose control. Bottom line: being sedentary is deleterious to health.

8) Getting older? Make it a point to move more. Regular leisure-time exercise patterns drop from childhood to adolescence and become unacceptably low in adulthood. One reason may be that we spend many hours at our desks working—with little time for leisure or even vacation. This is why it’s even more important to make an effort to fit in exercise as often as possible. And try to get up from your desk at regular intervals….and walk (even around the office) if you can. Remember, every little bit helps!

Who else needs to see this? Share it now.

Nancy Clark MS RD CSSDAbout Nancy Clark MS RD CSSD
Nancy Clark, MS, RD, CSSD (Board Certified Specialist in Sports Dietetics) counsels both casual and competitive athletes at her office in the Boston area (617-795-1875). Her Sports Nutrition Guidebook, Food Guide for Marathoners, and Cyclist's Food Guide all offer additional information. The books are available at and