Dr Dingle's Blog / biggest loser

Exercise for Weight Loss

Exercise for Weight Loss

Exercises on television shows like “the biggest losers“ give a false impression of the role of exercise. Exercise, unless it is extreme in the case of the biggest losers who have cameras and personal trainers and doctors etc. plays a relatively lesser role in weight loss and may even backfire in people who over do it. That doesn’t mean you don’t do anything because being active is critical for many aspects of your overall health and wellbeing were just saying you don’t have to be a gym junkie to get to your optimal weight. A lot of evidence shows that aerobic exercises which are great for the heart are minimally effective for weight loss, although they have multiple other benefits including reducing your risk of all forms of chronic illness. The problem is that, in general terms, exercise does not burn tons of calories (unless we’re doing heroic amounts of it). It doesn’t usually take much additional eating to wipe out any calorie deficit induced through exercise. For example the energy burned while walking 30 minutes (170 calories) each day will only lose you around one kilogram after 50 days. In the study, 23 overweight and healthy men engaged in a 6-month programme of exercise 108 minutes of exercise a week changed the expression of about a third of the genes in the fat cells, including some that relate to the risk of type 2 diabetes and the development of obesity. As well as changes in waist circumference, waist-to-hip ratio, diastolic blood pressure (the lower of the two blood pressure readings), resting heart rate and levels of HDL-cholesterol. However, weight only declined by 1 kg on average and appeared to be no less fat for their efforts.

In a meta analysis of children’s weight loss, Physical activity interventions were not associated with reductions of BMI. However, there was an association between the interventions and reduction of blood pressure. In a study of overweight people expending either 300 or 600 calories a day exercising for 12 weeks twice the exercise did not translate into improved weight loss. Those doing 300 calories of exercise lost an average of 2.7 kg compared to 3.6 kg for the 600 calorie exercise group. Double the exercise lead to a 30% extra loss of weight. Of interest those exercising for about half an hour a day (300 calories) had a more positive attitude to exercise. Doing larger amounts of exercise are harder which is a barrier to maintaining the exercise.

On the positive side exercise is great for keeping weight off. The more you are active the less likely you are to put on excess weight. In a study of 25 639 men and women an increase in weight was associated with higher risk of being inactive 10 years later. Compared with stable weight, a gain in weight of more than 2 kg per year is associated with physical inactivity 

Exercising for weight loss

But don’t stop exercising if you like exercising just yet because the level of exercise also has a large impact on your Resting Metabolic Rate and thermogenesis. There are certain things you can do to improve your weight through exercise. The first is to increase your muscle mass through anaerobic, muscle building exercise. The more muscle you have the higher your resting metabolic rate. That is the more you burn excess fuel while you are resting

You can also use exercise and physical activity to increase your thermogensis at critical times, in a sense tricking you body into burning calories before it is stored around your waist. Insulin is a major contributor to weight gain. The more insulin released with a carbohydrate dense meal the more weight you put on around the waste. However, increasing physical activity soon after a meal, even just standing up increases the cells requirements for the sugar without releasing extra insulin. Within seconds of any physical activity one of the non-insulin sugar pathways into the cells, the Glut 4 transporters are activated to remove sugar from the blood. This reduces blood glucose levels and improves insulin sensitivity (very good for diabetics). That is less insulin does more work. Regular exercise also increases the number of Glut 4 transporters. The more you exercise the more Glut 4 transporters your body will make. Any diabetic will tell you that as soon as they exercise their blood sugar levels goes down straight away. This means less to be stored as fat around the waist. In a study of thirteen obese-patients with type-2 diabetes post-dinner resistance exercise improved both postprandial glucose and glycation-end products, the damage caused by sugar. Post meal physical activity takes the sugar out of the blood before it can cause harm and build up around the waist. Associated with the increase in Glut 4 transporters is that exercise also increases the production of mitochondria which are the energy burning factories of the cells, and a lack of exercise causes numbers to deteriorate.

Exercise for your hunger genes

Like the different foods exercise can also alter how hungry you feel. In its natural environment your body is in perfect balance and everything feeds back on itself to constantly bring it back into balance. While being more active and exercising generally sends messages to eat more, to keep it all in balance you can also use exercises to suppress your appetite and trick the body. Exercise can suppress appetite, subsequent energy intake, and alter appetite-regulating hormones for a period of time post-exercise. Most people experience appetite suppression following an acute bout of exercise as exercise reduces your immediate feelings of hunger. In a study of 9 women who had fasted for some time before the experiment. They found that appetite ratings of the subjects in the exercise group fell for up to 2 hours after they had been placed on a treadmill for 30 minutes. Similar results have been found with different types of workouts and generally the exercise with greater metabolic and mechanical demand (weight-bearing exercise) showed greater immediate appetite suppression. So if you are reducing your calorie intake it is worth being active before a meal as well to reduce those immediate hunger pangs.

There is just no down side to physical activity unless you try to do too much too quickly like the biggest losers.

Standing up for weight loss

Sitting for any length of time may not be good for us, as more and more evidence shows that sedentary behaviours including sitting, watching television, using a computer, and driving a car are risk factors, independent of physical activity, for adverse chronic disease in adults such as obesity, diabetes, heart disease and much more. You can do a long run every night, but if you sit too long during the day you still increase your risk of these chronic conditions. In a study of 2,761 women and 2,103 men without clinically diagnosed diabetes, sitting time was detrimentally associated with waist circumference, BMI (body mass index), weight gain, blood pressure, fasting blood fats, HDL cholesterol, two-hour postload plasma glucose, and fasting insulin. A sure way to put on weight. In a meta-analysis using 48 studies, a consistent relationship of sedentary behaviour with mortality was found with weight gain from childhood. That is, the greater the sedentary time in childhood, the greater the weight gain.

It appears that any type of brief, yet frequent, muscular contraction throughout the day—such as standing or moving—may create healthy epigenetic signals which positively alter the body’s biochemistry and metabolism. One of these is a particular muscle chemicals, lipoprotein lipase (LPL), a protein enzyme has been studied in depth because this enzyme has a central role in several aspects of fat metabolism. Experimentally reducing movement by sitting had a much greater negative effect on LPL regulation than a positive effect of adding vigorous exercise training on top of the normal level of non exercise activity. In rat studies the amount of time spent sedentary influences how our bodies process fats given that leg muscles only produce the lipase lipoprotein (LPL) fat-processing molecule when they are being actively flexed, either standing or moving. What this shows is that by simply standing up more frequently you increase your muscle activity to reduce sugar and fats in the blood. To achieve even better effects you can stand up after a meal rather than sitting down and watching Television. In support of this one study reported that independent of total sedentary time and moderate-to-vigorous intensity activity time, increased breaks in sedentary time were beneficially associated with waist circumference, body mass index, triglycerides, and 2-hour plasma glucose. While in a study of 70 adults involving sitting for nine hours, regular activity breaks lowered plasma insulin levels and lowered plasma glucose when compared with prolonged sitting, even when compared with physical activity. While physical activity lowered plasma triglyceride more with regular activity breaks, activity breaks were more effective than continuous physical activity at decreasing negative blood sugar and insulin levels in healthy, normal-weight adults.

Overall, there is a compelling case for sitting reduction to be included in clinical preventive advice as a key component of “active living,” where adults and children are encouraged to “stand up, move more and sit less” across different settings and locations throughout the day. Just standing up every 20 or 30 minutes can have a remarkable health benefit reducing your risk of many chronic illnesses. How simple is that. The results of these studies suggest that, at a minimum, we need to be breaking up our sitting time every 20 to 30 minutes.

Read more →