Weight Loss Myths | Carson Tahoe Health

Dr. Q. Nguyen, Endocrinologist

Myth: Water exercises are cumbersome, less effective at burning “stored energy” and should be reserved for those who are obese or old.

By: Mary Sanders & Dr. Q. Nguyen, Endocrinologist


Extensive media coverage of only one study conducted on swimmers has led to the myth that exercising in water was not effective for weight loss.  Even Oprah Winfrey’s personal trainer quoted the study on her show which spurred more inaccurate perceptions.


Bust the myth: Water’s natural resistance and buoyancy provide a safe and effective exercise environment to build muscular endurance and expend kilocalories (kcal) for energy.  Water minimizes the pounding impact of gravity against the joints, which can provide a more comfortable environment for vigorous exercise, unsafe for many people on land.


As the speed of (any) movement increases, the “cost” of energy increases and you burn more kcal for fuel, making water a safe, comfortable and efficient way to “no sweat” exercise.


Alert: In post-exercise, watch out for the “hungries”. Investigators found that after immersion in water both cool and warm water, participants tended to eat more kcal, so be ready with a healthy, snack after your pool workout.


How to Correctly Exercise in the Water: Water exercise can be done in either shallow water or deep water. Shallow water is naval to armpit depth, 50-75% lower impact compared to land. If you find that doing exercises in shallow water hurts your feet, strap on a buoyancy belt and move to deep water. Deepwater provides you with zero impact.


To maximize your workout, use intervals. Push with maximal effort (Moderate-Hard) until you need to take a break and then slow down for recovery. Try to accumulate 10-20 or more minutes of moderate-hard intervals (30 seconds to 1 minute each).  Estimated kcal for 150 lb person for the work intervals:

10 minutes = 60-80 kcal

20 minutes = 120-160 kcal

30 minutes = 180- 240 kcal


If you’re strong enough to keep going, 30 minutes of shallow water kicking and running can “cost” you 249-510 kcal depending on how hard you are working. Deepwater running for 30 minutes can burn 390 – 450 kcal, with zero impact.

See the graph below for example exercises and the estimated kcal expenditures of each for a 150lb person.

Exercise Intensity Speed (Repetitions per minute) *RPE Rate of Perceived Exertion Estimated Kcal/minute for 150 lb person
Jumping Jax 110-120 Light 3-5
130-140 Moderate 6-8
Scissors 110-120 Light 3-5
Kick forward 110-120 Moderate 6-8
120-130 Hard 9-12
Kick sideways 110-120 Moderate 6-8
Run in place 110-120 Moderate 6-8
Run at max speed across the pool Max speed and effort Very hard ~17
Deepwater running Max speed and effort Very hard 13-15

*Rate of perceived exertion describes how hard the exercise should feel.



Myth: Eating after 7 PM will cause weight gain.

By: Karmella Thomas and Dr. Q. Nguyen, Endocrinologist


When starting a new diet plan for weight loss, people usually start by creating a “cut off” point for their evening eating. But, does eating after a certain time in the evening, like 7 PM, really cause weight gain?


Bust the myth: Although the research is limited in answering this question, there isn’t any evidence to confirm eating more calories at night causes weight gain.  It matters more about how many total calories you are consuming within a single day.  If you are consuming more calories than you need, you will gain weight.  The calories you eat at night are no different than the calories you ate at breakfast.


In fact, in a review of over 20 studies, France Bellisle reported that there is no clear evidence that points to how often or when people are eating their calories in relation to what we can expect with their weight2.  However, if you find yourself snacking more often after dinner, it’s a good idea to look at how much you’ve already eaten earlier in the day to determine if you can fit it into your calorie budget for the day.  One way to do this is to start by writing down your intake for at least a week.  If you are unsure of how many calories you should eat to maintain or lose excess weight, contact a Registered Dietitian.