Friday, May 13, 2016

How much sleep do I need?

In the last few years, it has become evident that sleep deprivation has a negative impact on ability to lose weight. Although there is much left to learn about the mechanisms involved, it appears that at least 2 things happen to you when you do not get enough sleep:

1) Leptin levels drop. Leptin is a hormone that influences your metabolism. When leptin levels drop, you burn fewer calories.

2) Ghrelin levels increase. Ghrelin is a hormone that influences appetite. The higher the ghrelin, the more hungry you will be.

For obvious reasons, the combination of burning fewer calories and eating more because you are hungry makes it tough to lose weight.

Many studies over the last 10 years have shown a decreased metabolism and/or increased energy intake with sleep deprivation.

So, how much sleep do you need? Most studies show that 7 hours or more are what you are looking for. I have also found this to be true with my own clients.

Take a good look at your sleeping habits. Sleep deprivation can often be a little thought of, but very important component of your weight loss program.

Energy and macronutrient intake after gastric bypass surgery

The Study
Gastric bypass surgery is an effective strategy for weight loss in the severely obese when diet and exercise has not been effective. However, in most cases, 40-50% of lost weight is regained after several years and it is not clear why this is the case.

In this study, 16 women were followed for 3 years after bypass surgery. Total energy, lean body mass, and basal metabolic rate were measured at regular intervals during the follow-up. By the end of 12 months, the women had lost an average of 87 lbs.

At baseline, calorie consumption was 2,072 per day.

At 1 month post surgery, it dropped down to 681 calories.

At 12 months post surgery, it increased to 1240.

At 36 months, it increased to 1,448 calories.

As far as basal metabolic rate:

At baseline, it was 1.1 kcal/minute.

At 3 months it was .93 kcal/minute.

At 12 months it was .86 kcal/minute.

At 36 months is was .85 kcal/minute.

By the end of 1 month, 51.6% of weight lost was lean body mass. By the end of one year, 24.5% of weight lost was lean body mass. By the end of 36 months, 30% of weight lost was lean body mass. American Journal of Clinical Nutrition 2016; 103:18-24.

Take Home Message
This is a really important study, not just for those who have bypass surgery, but for everyone looking to keep lost weight off for good. Over the 3 years of this study, we saw a gradual increase in caloric consumption, a gradual decrease in basal metabolic rate, and a very significant loss in lean body mass.

Remember, lean body mass burns calories and is highly related to metabolism. You lose muscle, your metabolism drops and weight regain is far more likely. 

This study shows why a lot of people who get gastric bypass surgery regain their weight. They are the same reasons why the rest of us regain our weight; calories shoot back up and metabolism drops. 

The body may lower metabolism in response to weight loss. There is not much we can do about that. However, we can minimize loss of muscle mass by lifting weights consistently throughout the weight loss process and during weight maintenance. Keeping a close eye on caloric consumption is also essential to keeping the weight off.

This study would have been perfect if half the women were randomized to a weight lifting routine post surgery to compare basal metabolic rates and percent lean body mass lost.

Thursday, May 12, 2016

Probiotics and Weight Loss

The Study
Probiotics are live micro-organisms that have been shown to improve varying aspects of health when consumed in the proper quantities. It has been hypothesized that they increase rate of weight loss. In this randomized controlled trial, 89 overweight and obese women consumed a standard low fat yogurt, or a probiotic yogurt, for 12 weeks while following the same comprehensive weight loss program.

At the end of follow-up, women in both groups lost similar amounts of weight. However, the women consuming the probiotic yogurt had a 13.9 mg/dl drop in total cholesterol and a 13.5 mg/dl drop in LDL cholesterol when compared to the standard low fat yogurt group. They also had significant improvements in blood glucose and insulin levels. American Journal of Clinical Nutrition 2016; 103:323-29.

Take Home Message
This is a very nicely designed trial with a simple message. Probiotics can definitely improve certain health parameters but do not appear to increase the rate of weight loss. We are just beginning to learn about the health effects of the gut microbiota, but it appears to be an extremely important and complex element of good health. Unfortunately, it does not look like a quick fix for weight loss.


Feature Article: Do vegetarians live longer than meat eaters?

Vegetarians tend to avoid meat for one of 2 reasons, they think it is unhealthy to eat meat or they have an ethical issue with doing so. If they are motivated by ethical factors, that question is beyond the scope of this newsletter. If they are motivated by improved health, we can ask the question; Are vegetarians healthier than meat eaters? Do they live longer?

I recently came across a study that attempts to answer this question.

Mortality in vegetarians and comparable nonvegetarians in the United Kingdom. American Journal of Clinical Nutrition 2016;103:218-230.

This study was a pooled analysis of 2 prospective cohort studies in the UK that totaled 60,310 subjects: 

18,431 were regular meat eaters who ate meat 5 or more times per week.

13,039 were less frequent meat eaters.

8,516 were fish eaters who ate fish but not meat.

20,324 were vegetarians including 2,228 vegans who did not eat any animal foods.

Diet was assessed by means of a food frequency questionnaire. After over a million person years of follow-up time, there were 5,294 deaths before the age of 90. By the end of follow-up, there was no significant difference in total mortality among the 5 groups.

In other words, vegetarians and vegans did not live any longer than those that ate meat or fish.

I was not really surprised by the findings of this study. The idea that meat eaters are unhealthy while vegetarians are healthy is far too simplistic. There is a whole lot more to the story.

#1) Protein itself is not really the issue. It is what comes along with the protein package that will determine a food’s impact on health.

Healthy sources of protein will be low in saturated fat, unprocessed, low in sodium, and not red in color.

Examples of healthy protein sources would be lean meats like chicken and turkey, low fat dairy products, legumes, nuts, fish and seafood. You can see that some of these are animal sources and some are not.

Proteins you want to go a bit easier on include red meat, processed meats (like bacon, sausage, pepperoni, and hot dogs) and full fat dairy products like cheese. Again, some of these are animal sources and some are not.

2) When evaluating the health impact of a diet, you have to look at more than just the source of protein. For example, what is the quality of carbohydrate consumed? What type of fat is being consumed? If you are eating a ton of saturated fat, sugar and high glycemic load carbs, you are not going to be healthy no matter what protein sources you are focusing on.

For example a meat eater and a vegetarian can go out to a restaurant for lunch and order the following:

1) Meat eater: A garden salad with grilled chicken and olive oil and vinegar dressing, a glass of club soda with lime and a bowl of strawberries for dessert.

2) Vegetarian: Pasta Alfredo with two big pieces of bread, 2 sugary sodas and an ice cream sundae for desert.

Who did a better job, the vegetarian or the meat eater?

So, the take home messages from this study are the following:
1) Lean sources of animal protein like chicken, turkey, fish, and seafood are not bad for your health. There is no reason to avoid them.

2) The protein sources to strictly limit include processed meats like bacon, salami and hot dogs, red meat, dairy products like cheese, yogurt and milk that are full fat.

3) There are other important factors besides the source of protein in your diet that will impact your risk of chronic disease. Make sure you are paying good attention to your sources of fat and carbohydrate. Other important areas that need attention are your weight, exercise habits, sleep and stress levels.

Sunday, March 13, 2016

If I Am Not Hungry, Is It OK To Skip Breakfast?

It has been a really big surprise to me as a nutritionist to learn just how many people don’t eat breakfast in the morning.  I, for one, am starving when I wake up and have been ever since I have been a little kid. I don’t know how anyone can wait until lunch for their first calories of the day. Either way, I am often asked if it is OK to skip breakfast, particularly by those looking to lose weight.

Will skipping breakfast impact one’s ability to lose weight?
The research goes back and forth on this one and I don’t think we really do know for sure. I have seen evidence of a decreased weight loss in breakfast skippers and I have seen evidence that there is no difference in weight loss when comparing breakfast eaters to those who skip breakfast.

I can tell you this anecdotally, in the last 15 years, every one of my clients who hits their goal weight eats breakfast. Here is my theory as to why it is important:

Since humans evolved in times of famine and food scarcity, I feel that over the years our bodies developed defense mechanisms to protect us from these events.

When food starts to get in short supply, I believe that our body tries to prevent fat stores from dropping too low. This is accomplished 2 ways. #1) Our metabolism slows down so it takes fewer calories to get through a day. #2) In an effort to preserve fat stores, we start to burn muscle for energy. There is evidence of this in the research literature. When people lose weight by really restricting their calories, you start to see a lower metabolic rate and a significant loss of lean body mass.

Say you eat dinner at 6:30 PM, go to bed, skip breakfast and eat at noon the next day. You have gone 17½ hours without eating food, almost a full day. I believe that this does bad things to your metabolism and makes it harder to lose weight. It is also my opinion that when the body notices a steady and consistent supply of calories every few hours, it is more likely to release its fat stores, and that is why I don’t like my clients to skip breakfast. Again this is my theory, I don’t think there has been enough research on these defense mechanisms to prove or disprove them.

Some other reasons to eat breakfast:
1) It will help keep your blood sugar stable, which has a very nice impact on your energy, mood and ability to focus.

2) When you skip breakfast, you tend to make up the calories by snacking. In general, snack foods aren’t as healthy as planned meals.

3) I don’t think it is possible to get all of the good nutrition your body needs in a day in just two meals. Eating three meals makes it much easier to hit goals for fruits, vegetables, protein, vitamins, minerals, fiber, anti-oxidants, etc.

So in conclusion, everyone should eat a healthy breakfast. This is especially important if you are trying to drop a few pounds.


Prebiotic Consumption And Risk Of Weight Gain

The Study
Prebiotics are fermentable carbohydrates that our body can’t digest. They have the ability to alter the composition of our gut microbiota and are thought to confer a number of health benefits. However, most studies on prebiotics have been on animals and research in humans is sparse.

In this investigation, 8,569 normal weight subjects from the Spanish Sun Project cohort had their diet measured by a food frequency questionnaire and self reported their weight every two years. The subjects were split up into 4 groups according to their consumption of prebiotics. After 9 years of follow-up, the group consuming the most prebiotics had a 13% lower risk of becoming overweight when compared to those consuming the least. American Journal of Clinical Nutrition 2015; 102:1554-62.

Take Home Message
The connection between our gut bacteria and our weight is fascinating and is still in the process of being elucidated. There really does seem to be a connection. Prebiotics are used as an energy substrate by healthy bacteria in the gut that convert them into short chain fatty acids. These short chain fatty acids are thought to influence levels of certain hormones, like peptide YY and glucagons-like peptide 1, that may influence satiety and decrease food consumption. 

In this cohort, most of the prebiotics that were consumed came from fruits, vegetables, legumes and whole grains. If you need yet another reason to eat these healthy foods with regularity, here you have it.

Diet Soda Vs. Water For Weight Loss

The Study
Sixty-two obese and overweight women initiated the same weight loss plan, which included a low calorie diet and 300 minutes of moderate exercise per week.  Half of the women were told to drink at least one diet beverage after lunch and the other half were told to eliminate diet beverages and drink only water. Body weight and several metabolic indicators were measured both before and after the 24 week intervention. Both groups lost a significant amount of weight. The diet soda drinkers lost an average of 16.7 lbs., while the water drinkers lost 19.4 lbs. Furthermore, the women drinking the water had a statistically significant improvement in insulin sensitivity when compared to the diet soda drinkers. American Journal of Clinical Nutrition 2015; 102:1305-12.

Take Home Message
This was a very well designed trial that taught us a few things: 1) Water is, far and away, the beverage of choice for weight loss. 2) Drinking diet soda regularly does not prevent weight loss, if the diet and exercise program is strong. A couple of studies I have read in the past few years hypothesized that consistent diet soda consumption interfered with the ability to lose weight. This study shows evidence that this is not true. However, the water drinkers lost more weight over the 24 weeks and had an improvement in insulin sensitivity, which translates to a lower risk of type 2 diabetes.

If weight loss is your goal, make water your primary beverage. If you love diet soda, have a couple a week as a treat.  If you are drinking a lot of regular soda now, switching to diet can be a nice and easy option to start the scale moving in the right direction as you transition yourself to water as your go to beverage.