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Weight management, Physical Activity & Sleep- Their Affects on Metabolism by Richa Mittal, MD

This weekend I reached out to Richa Mittal, MD, internist and founder of the concierge medical weight loss and preventive health care practice, Radiant Health Weight Loss and Wellness. I was interested to learn more about how weight management, physical activity and sleep affect one another and our overall metabolism.

Why is it important to have a comprehensive approach to weight management and preventive health?

Metabolism, weight, and health are the result of complicated and inter-related processes that affect each other. When treating people for overweight and obesity, it is important to remember this concept and try to optimize the pillars of health through nutrition, physical activity, adequate sleep, and stress management. It is also important to address psychological factors like underlying depression, habits and behaviors and work on mindful eating, when coming up with a treatment plan. Many of us have turned to food in times of stress, habits or boredom. For effective life-long change, we have to recognize when this happens and find other ways of coping. Of course the medical aspects of inflammation caused by the accumulation of fat, genetics, medication-effects and endocrine abnormalities are evaluated and treated as well. 

What are the effects of physical activity with weight loss and how much is enough?

A review of NHANES (National Health And Nutrition Examination Survey) in 2015, looked at what impact lifestyle factors played on health. They found time spent on moderate to vigorous activity had a significant association with BMI, waist size (indicates excess of fat around our organs that raises risk for type 2 diabetes and heart disease), insulin resistance and type 2 diabetes, and blood pressure. 

Current recommendations from the WHO is at least 150 min of moderate-intensity aerobic physical activity or 75 min of vigorous intensity physical activity per week plus muscle-strengthening activities 2 or more days a week. It is estimated that 65% of Americans do not get the recommended level of physical activity. 

So, is exercise important for weight loss? It is, but during maintenance of weight loss. We have all heard the saying: “You can’t outrun a bad diet." Interestingly, after a person has lost weight, the person’s metabolism slows down, as in their resting energy expenditure decreases. This is why, in order to maintain metabolic mass, it is important to ramp up muscle-resistance training. 

According to the American College of Sports Medicine, one has to exercise 225-420 min/week to promote weight loss and exercise 200-300 mins/week to prevent weight regain after weight loss.  Another way of maintaining weight loss is to maximize NEAT: Non-exercise activity thermogenesis, i.e. the calories we burn doing activities other than formal exercise. Examples of this are taking the stairs, working at a standing desk, or playing outside with your kids! There are higher levels of a neurotransmitter called orexin in the brains of people who are “movers”. They tend to be leaner- so get moving!

How does sleep affect metabolism?

According to many studies, it has been found that 7-8 hours is the ideal amount of sleep. People who sleep less than 5 hours a night have higher odds of being overweight and are twice as likely to have obesity (BMI over 30). Even those who sleep between 5 and 6 hours a night have a greater odds. 

Why is this? It is likely related to the hormonal responses to sleep disruption. Lack of adequate sleep has been linked to higher levels of hunger hormones (like grehlin) and lower levels of satiety hormones that tell us we are full (like leptin). This results in an increased appetite. Similar effects are seen with people who have disruption in their circadian rhythms, like those who do shift work.   

Other metabolic hormones affected by lack of sleep are insulin, leading to decreased insulin sensitivity (aka insulin resistance and risk for type 2 diabetes), as well as, an increase in evening cortisol and growth hormone during the day, leading to higher blood sugars and insulin resistance.

As you can see, it is so important to optimize so many aspects of our lives. Weight and metabolism are not simply a function of calories in and calories out. Good nutrition is about eating real food. A healthy lifestyle needs to include not only good food, but also prioritizing physical activity and rest so we can live our best lives. 

Richa Mittal, MD

Dr. Richa Mittal is an internal medicine and obesity medicine physician with her own preventive health and weight loss practice called Radiant Health Weight Loss and Wellness in the Dallas suburbs. 

She enjoys providing one-on-one, personalized care to her patients. She provides medical treatment, serves as their health coach, provides nutrition & lifestyle counseling and guidance for strategies like fasting. She finds it so exciting to help people prevent and reverse chronic diseases!

She also enjoys creating and sharing healthier versions of recipes. In addition, she has a blog that focuses on education and a newly launched video blog on YouTube!

She is passionate about spreading education about food as medicine!

Contact information:

LinkedIn: Richa Mittal

Website & health blog:

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