Exercise, Hunger and Weight Loss

Exercise, Hunger and Weight Loss

If we exercise more then metabolism increases and we eat more. If we exercise less then metabolism decreases and we eat less. Sometimes the increased food intake caused by more exercise will sabotage weight loss efforts by offsetting the calories burned with more exercise. By understanding a few key hunger hormones we can tailor our exercise to minimize the hunger response.

The Hunger Hormones

Leptin and ghrelin are the main players in appetite. Leptin is made by fat cells and manages hunger on a day-to-day basis by telling our brain we are satiated or full and speeding up our metabolism. Ghrelin is made by an empty stomach, sends the message that we are hungry, and slows down the metabolism.

Exercise will affect both leptin and ghrelin, but different exercise has different effects. Moderate intensity prolonged exercise will increase the appetite while higher intensity shorter duration exercises have an appetite suppressing effect. It seems that low intensity activities such as casual walking has a neutral effect.

The longer duration moderate exercises such as swimming or running increases ghrelin and suppresses leptin. The short duration intense exercise such as sprinting or interval training will suppress both leptin and ghrelin.

Some studies show that doubling the exercise time will not result in twice the weight loss. It appears that the shorter duration intense exercise or the longer duration low intensity exercise will result in the least amount of hunger caused by the exercise itself.

Home programs such as P90X and Insanity are examples of more short duration high intensity programs. The interval training methods with peak intensity are also shown to promote the fat-burning-muscle-building hormone called growth hormone. (see my past columns on “high-intensity interval training” and “steps to super wellness”)

The increased appetite associated with exercise gives cause to consider just what food is consumed after exercise. This is especially true with high intensity exercises and strength training. This is the time to consider “recovery drinks”.

During and for a few hours immediately after exercise the body is primed to absorb nutrients, break down fat and rebuild muscle. What we feed the body has a huge impact on this process. A nutritious recovery drink can really improve the body’s response to your exercise efforts. (see my past columns on “sports nutrition”)

The Role of Insulin and Glucagon

Insulin is another key player in hunger. It is similar to leptin in that high levels of insulin will tell our brain we are full. Insulin is a “storage” hormone produced by the pancreas in response to a meal. It responds to high blood sugar levels by opening up muscle and liver cells so that glucose may leave the bloodstream and encourages excess glucose to be stored as energy that can be burned later. During and immediately after exercise insulin helps turn on protein building in muscle. During rest insulin encourages fat storage.

Glucagon is another hormone from the pancreas and is considered as the opposite of insulin. It responds to low blood sugar or a high protein meal by stimulating the release of stored glucose from the liver.

When all goes well our hunger hormones are an elegant system of appetite and metabolism control. During times of feast leptin signals the brain we are full and turns up metabolism while insulin stores the excess calories. During famine, ghrelin alerts our brain to get moving and find something to eat, while glucagon breaks down stored glucose to provide fuel for the energy to hunt down that next meal.

So where do things go awry? Starting with high calorie nutrient poor foods, coupled with lack of exercise and topped off with an aging metabolism, we tend to store calories and weight goes up. Once the extra weight builds up insulin and leptin both become less effective. We keep making more and more but our helpful hunger hormones just quit working as our body becomes more resistant to their effects.

As an example, Type 2 diabetics have insulin resistance. Once fat starts building up in muscle and liver tissue, insulin resistance sets in and we can’t handle the glucose in the bloodstream. This starts a vicious cycle since high blood sugar leads to high blood triglycerides, while high insulin levels encourage more fat storage. Even the first 10 pounds of extra weight will cause some degree of insulin resistance.

Leptin resistance also occurs with weight gain. Similar to insulin in the diabetic, we make more and more leptin as we gain weight, but it quits working to signal the brain that we are full, thus leading to a cycle of persistent hunger pains.

Keys to Weight Control

Work with the hunger hormones to keep appetite under control. Get the right kinds of exercise. Give the body the right types of recovery nutrients after a workout. Eating patterns in general can encourage the hunger hormones to work for you instead of against you.

Help insulin work by cutting out insulin spiking foods such as sugar and high-glycemic carbohydrates. Eat more complex carbohydrates including greens and other colored vegetables and fruits. Exercise increases insulin sensitivity so take a 15 minute walk after eating. Insulin is hard at work in muscle tissue so include a bit of resistance or strength training.

Include protein at every meal for good metabolism, to help stabilize insulin spikes, provide building blocks for muscle and to encourage glucagon release. This means lean meats and fish, eggs, milk, cheese, yogurt, and beans.

Don’t skip breakfast! If you don’t take in some calories first thing in the morning, as a “break from the overnight fast”, then your body will go into emergency mode, releasing the stress hormone cortisol and breaking down stored glucose for fuel. This causes a quick insulin spike and leads to irregular sugar / insulin balance throughout the day. Insulin spikes lead to insulin resistance whereas the smooth release of insulin from the intake of complex carbohydrates and protein is much more efficient.

Try a “wake-up” protein if you don’t get to breakfast right away. Whey protein isolate or concentrate in plain water, or mixed in a smoothie, is an excellent complete protein source. Studies show that eating breakfast and especially including protein at breakfast leads to less hunger and less weight gain.

Sleep is a very important suppressor of ghrelin, and poor sleep will increase ghrelin levels leading to increased appetite the next day. Interestingly, ghrelin helps us get into a good sleep cycle, so going to bed with a full stomach and low ghrelin can interfere with sleep. Don’t eat a big meal just before bedtime and be sure to get enough sleep.

We use a variety of targeted supplements that help insulin and leptin work better. Our staff exercise physiologist specializes in developing custom workouts and diet plans that can help your exercise efforts better target your friendly hunger hormones.

INSET
FREE SEMINAR
Low Thyroid: Misunderstood, Misdiagnosed, Missed!
Monday, June 4th at 6pm, at the IMC.
Seating is limited so RSVP at 245-6911 or online at rsvp@imcwc.com.

Bio

Scott Rollins, MD, is Board Certified with the American Board of Family Practice and the American Board of Anti-Aging and Regenerative Medicine.  He specializes in Bioidentical Hormone Replacement for men and women, thyroid and adrenal disorders, fibromyalgia, weight loss and other complex medical conditions. He is founder and medical director of the Integrative Medicine Center of Western Colorado (www.imcwc.com). Call (970) 245-6911 for an appointment or more information.