The reaction to an editorial claiming that exercise alone will not help patients lose weight is illustrative of the biases held by certain groups and underscores the need for greater education and awareness of the science of weight loss for patients and clinicians.
In late April, the British Journal of Sports Medicine published an editorial by Dr. Aseem Malhotra and two other cardiologists that stated exercise alone will not help you lose weight. A variety of media outlets picked this up and the message of exercise’s lack of benefit rapidly went viral. Patients who were not exercising rejoiced, and the key message of the article was lost.
This article was so controversial the British Journal of Sports Medicine briefly took the editorial down. To be clear, the authors’ intention was to identify and call out the food industry in its role in the worldwide obesity epidemic. Instead, it prompted a variety of parties to claim that exercise is no longer needed and undermined hours and years of beneficial health care messages.
There is an enormous set of data that supports the many benefits of exercise. For weight loss, exercise actually is effective, especially for those who are obese. Its immediate effects, if the exercise is performed later in the day, include reducing serum glucose levels, triglyceride levels, insulin levels, and increased calorie expenditure. In fact, a systematic review and meta-analysis conducted in 2013 found the two most important changes a pre-diabetic needs to make to prevent the progression to diabetes is to limit their carbohydrate intake and increase their activity.
For the obese diabetic, a number of articles support the influence of certain types of exercise on improved outcomes including weight loss. Sprint interval training is the most successful and involves doing Tabata training wherein the patient works in some “all-out” aerobic fashion for 30 seconds followed by 4.5 minutes of rest with repeat sets for a total of 6 cycles. This exercise approach improved both diabetic and cardiovascular risk factors as well as a result in a decrease in both waist size and overall weight.
There is also a large data set that supports cardiovascular fitness in lowering cardiovascular risk for both primary and secondary prevention. This is particularly important when one considers the amount of time the average person sits as part of their daily work life compared to just 30 years ago. When one considers how even just a little bit of exercise in obese patients can improve outcomes, one can quickly recognize that Malhotra’s editorial has been taken out of context and manipulated. The intent of the editorial was his observation of the critical need for obese patients to eat less (especially commercially prepared foods) to lose weight and to decrease their metabolic and cardiovascular risks.
What to do clinically? First, tell patients that even if they are not obese, exercise must be a critical component of their daily adult life. Minimally 20 minutes 5 days a week for primary prevention, and 40-60 minutes 5 days a week for patients with multiple cardiovascular or metabolic risk factors. When to exercise? Some data suggest you get the best weight loss with exercise done later in the day. There is increasing data that exercise after meals, even as little as a 15 minute walk 3 times a day after meals, has a huge impact for patients with limited cardiovascular fitness. And for those at average risk, a small randomized trial compared sitting for 9 hours a day to exercise in the morning and then sitting for 9 hours a day versus taking a 100 second walk every 30 minutes. It is only the brief walk every 30 minutes that had the best outcomes.
I have two signs hanging in my examination rooms. One says: “A 1-Hour Workout is 4% of Your Day; No Excuses.” The other says: “He Who Takes Medicine and Neglects Diet Wastes the Skill of His Doctors.” I do not need to reference them during the course of patient care, as patients see them and bring them up on their own. It is critical we have a uniform front in addressing the obesity crisis. It primarily hinges upon decreasing the carbohydrate intake of our patients and getting them to be more active, particularly after meals and later in the day.