Monday, November 14, 2016

Raisins are a convenient and portable way to get my fruit, right?

As a derivative of fruit, it makes sense that most people think of raisins as a healthy food. My clients are usually quite surprised when I tell them that dried fruit needs to be strictly limited.

The problem with raisins arises during the drying process. Drying a fruit increases the sugar content dramatically and decreases the fiber. 

As you probably know, raisins are dried grapes. A serving of grapes (4 ounces) has a glycemic index of 43 and a glycemic load of 7, both of which are on the lower end (Reference 1). However, a serving of raisins (2 ounces) has a glycemic index of 64 and a glycemic load of 28, both on the high end (Reference 1).

The key to eating for weight loss is to maintain a stable blood sugar. This strategy helps to keep insulin at a reasonable level and significantly reduces hunger and subsequent energy intake.

Despite having some nutritional upside, eating raisins is very similar to eating candy when it comes to your blood sugar. If you are trying to lose weight, a much better choice is to go for fruit in its whole and natural form.

References
1) www.glycemicindex.com

Religious service attendance and mortality

The Study
Over 74,000 women in the Nurses’ Health Study had their religious service attendance assessed repeatedly by questionnaire and were followed for 20 years. By the end of follow-up, women who attended religious services more than once per week had a statistically significant 33% lower rate of mortality when compared to women who did not attend religious services. The association held after controlling for all known predictors of death in this cohort. JAMA Internal Medicine 2016; 176:777-85

Take Home Message
This is a fascinating study to me. You don’t see a lot of literature on the subject of religious beliefs and health outcomes, but the reduction in risk of mortality in this investigation is strong and impressive.   

The mechanism for the reduction in risk of death in the religious is not known. However, the authors suggest several possibilities:

 1) Increased social support

2) Lower levels of depression

3) Higher levels of optimism

4) Religious coping mechanisms

5) More purpose in life

6) More self discipline

7) Higher psycho-social resilience

It is certainly beyond the scope of this blog to make recommendations of a religious nature. However, I just wanted all of my readers to be aware of this association, because it appears to be a very important predictor of long-term health.

Can lifting light weights effectively build muscle?

The Study
In this study, 49 men that lifted weights regularly performed 12 weeks of resistance training. The men were randomly allocated to one of two training groups; the first group used very heavy weights (75-90% of 1 rep max) for 8-12 repetitions per set, the second group used much lighter weights (30-50% of 1 rep max) for 20-25 repetitions per set. Each group lifted weights 4 times per week. At the end of follow-up, there were significant increases in muscle mass in both groups with no difference between groups. Journal of Applied Physiology 2016; 121:129-138.

Take Home Message
This study shows that you don’t have to lift very heavy weights in order to build muscle. You can get similar increases in muscle mass with lighter weights and higher repetitions. I use lighter loads with most of my clients, for a bunch of reasons: 1) I find there is a lower risk of injury. 2) It is my opinion that it is safer (lower spikes in blood pressure and heart rate) than using much heavier weights. 3) I find there is a lower risk of overtraining with lighter weights. 4) Generally, it is more enjoyable. Experienced weight lifters actually enjoy the fatigue and “burn” that comes with lifting heavy weights. Most people that are new to weight lifting and that are deconditioned do not. 

This study shows us that you can build muscle quite well with lighter loads, as long as you increase your repetitions.

Product Review: PT Pro Fitness Bench

As a trainer and nutritionist working with weight loss clients, I have noticed for years that clients who exercise at home get much better results than those that go to a gym.

If you want to stay in shape and at a healthy weight as you get older, exercise has to be a daily event. Most of my clients do cardio every day and hit the weights at least two or three times per week. Given our busy lives, is it realistic to expect to get to the gym every day? For just about everyone, the answer is no.

There are several reasons why working out at home is better than joining a gym:

1) It takes much less time to workout at home. If you have to get in your car, drive to the gym, get changed in the locker room and then do the same thing in reverse, you have just turned your 40 minute workout into an hour and 20 minute ordeal. It’s just too easy to blow off. 

Furthermore, at a gym you may have to wait for someone to finish using the cardio or weight training equipment you want to use. This adds even more time.

2) It is just more convenient. If I am watching my kids, I can take them downstairs to play while I hit the weights for 20 minutes. I can’t bring them to the gym. I can also combine my exercise with something I need to do if I workout at home. I can return phone calls, check my email, read the paper, watch the news, etc, all while doing cardio. When I was in grad school, I even used to study while doing my cardio. It is hard, if not impossible, to do these things at the gym.

3) It is much cheaper over the long term. Gyms can be quite expensive. The cheaper $10 a month gyms that are popping up are great, but they may not be convenient to you. Say your gym costs $70 per month, or $840 per year. In 5 years, you have spent $4,200. You can set yourself up with a really nice home gym for a fraction of that amount that will last you for decades.

A great place to start for any home gym is a set of dumbbells and an exercise bench. Enter the PT Pro Portable Fitness Bench. This bench is perfect for people that don’t have a lot of space and/or don’t want to look at their exercise equipment on a regular basis.

Here are some of the benefits of this bench:
#1) It folds up for storage. The legs of this bench fold up so you can store it in a closet or under your bed. This is a great feature if you live in an apartment and don’t want your bench taking up valuable space. For most of my time in Boston, I had a tiny apartment and this feature was critical.

#2) For fitness professionals; this bench is light weight and portable. You can bring it to a client’s home if you are an in-home trainer.

#3) The bench has both incline and decline capabilities, so you can add a lot more variety than you can with a simple flat bench.

#4) It is very well made. I’ve had mine for years and it is holding up extremely well. In fact, it looks and works as well today as the day I got it, which was 7 years ago.

Cost: It is not cheap at $299, but it is a one time expense. You will likely never have to buy another bench. It’s also a cost saver if it allows you to cancel your gym membership. 

For more information, here’s the manufacturer’s website:
http://jpdesignandmfg.com/product/ptpro-portable-fitness-bench-the-full-featured-portable-gym/

Note: I have no relationship with this company and do not make any money for promoting their products. I just have been really happy with my PT Pro and recommend it highly.

Tuesday, September 13, 2016

Is a low fat diet the path to weight loss?

It is completely understandable how low fat diets came to be popular. Before we had the tools to really study diet in large populations, it made a lot of sense. After all, fat contains 9 calories per gram, compared to 4 calories per gram for protein and carbohydrate. It seems logical that limiting the most calorie dense food would help one to lose weight. Now that our research methods are more advanced, we have had the opportunity to study the efficacy of low fat diets. It turns out that they really don’t work so well over the long term.

In a summary of the research literature, replacing 10-15% of dietary fat with carbohydrate results in a modest weight loss of 2-9 lbs. over the short term (6 months). However, over the long term (1 or more years) this weight is regained and there is no association between percent of dietary fat and body weight (Reference 1).

Why is this the case? For two reasons actually:

1) Dietary fat promotes satiety. It helps you feel full. Most people get really hungry a few hours after eating a low fat meal, particularly if it is high in carbohydrate and low in protein.

2) Dietary fat helps to stabilize blood sugar. Swings in blood sugar common with low fat, high carbohydrate eating patterns result in a reactive hypoglycemia that drives down blood sugar and increases insulin levels. For most people, this will result in increased hunger and overeating. 

Incidentally, these hormonal changes in blood sugar and insulin levels may also promote fat storage independent of caloric intake.

The most convincing evidence that low fat diets do not result in long term weight loss has been indirectly conducted right here in America over the past few decades. Our percent of calories from fat has steadily dropped from 40% of calories to 34% in the last 30 or so years. Have we gotten thinner? Not at all, obesity rates have skyrocketed in this time period.

References
1) Willett WC. Dietary fat plays a major role in obesity: no. Obesity Reviews 2002; 3:59-68.

A completely new way of thinking about weight loss

The Study
The prevailing wisdom about how to lose weight is to decrease calories and increase physical activity. This theory was put to the test in a very interesting study. One hundred and fifty four adolescents and 75 college age women underwent a two week baseline measure of their resting metabolic rate, energy intake, and body composition. Researchers created a variable for each subject called energy flux, which was calculated by adding energy intake and energy expenditure for each person. Subjects were then followed for 2 years to see who gained or lost the most weight.

The subjects with low energy flux were more likely to gain weight, while the subjects with high energy flux were more likely to lose weight. In other words, eating more calories and exercising a lot reduced the risk of gaining weight, while eating fewer calories and exercising very little increased the risk of gaining weight. American Journal of Clinical Nutrition 2016; 103:1389-96.

Take Home Message
This is a fascinating study that tells us 2 two things:

1) Exercise is extremely important for long term weight maintenance, which most of us already know.

2) Cutting calories a lot may not facilitate long term weight loss. This is a relatively new concept. 

Our body fights back really hard when we cut calories. Very few people can keep weight off long term when they lose it solely by reducing energy intake. The researchers believed that the reason the low energy flux group gained weight was largely due to significant decreases in resting metabolic rate as a response to the lower calorie intake.

Although this is just one study and more research is needed, it is becoming clear that weight loss is much more than just calories in versus calories out. The human body has awesome defense mechanisms to keep its body fat at what it considers to be a safe level. We have much to learn about these mechanisms.

I tell my weight loss clients to cut their calories slightly, not severely, and to make cardio and strength training a very consistent habit.

What influences appetite more, cutting calories through dietary restriction or through exercise?

The Study
In this randomized trial, 10 young men completed 2 separate interventions that created a 25% deficit of their energy requirements. This was done first by reducing calories by 25%, and later by exercising 25% of their calories away. Appetite and energy intake were measured after each condition. The results were a bit surprising. Despite the deficit being 25% in both interventions, subjects were significantly more hungry and ate more calories after reducing their food intake. American Journal of Clinical Nutrition 2016; 103:1008-16.

Take Home Message
For most people, losing weight over the short term is not that difficult. Keeping it off is the real challenge. We evolved in times of famine, drought and food scarcity. Our body developed some very good defense mechanisms to help keep our body fat at a safe level, including lowering metabolic rate and increasing hunger when faced with weight loss.

This study provides evidence that reducing calories creates more of this fight back response than exercise. This makes sense to me. I have noticed for years that drastic caloric restriction and rapid weight loss almost always results in an equally rapid regain of lost weight. I have found that the quicker the weight comes off, the quicker it comes back on. A more slow and steady approach to weight loss is imperative. Reducing calories moderately, but consistently, is the key. A well organized exercise program is the other part of the equation.