Thursday, November 12, 2015

Drinking Juice Is An Easy Way To Eat More Fruit, Right?

The answer is no, and let’s start with some background.

Fruit in its whole form is one of the very best things that you can eat. It is high in vitamins, fiber, low glycemic load carbohydrate, and phytochemicals. In the research literature, fruit consumption has been associated with a lower risk of heart disease, stroke, hypertension, and certain types of cancers.

The sugar in fruit in its natural form is surrounded by a helix of fiber. Your digestive system has to break through this fiber in order to digest the sugar. This takes time, so fruit in its whole form has a very easy impact on your blood sugar.

When you juice a fruit, you are separating the sugar from the fiber. What you are left with is pure sugar. This will cause a spike in your blood glucose and insulin levels, which is not a good state for the body. Over the short term, these spikes in blood sugar will leave you hungry a few hours later, so you tend to eat more at the next meal, which can add to weight gain. Blood sugar spikes also can negatively impact your energy and focus. Over the long term, diets with a high glycemic load have been associated with a number of diseases, including heart disease and diabetes.

Juicing a fruit or vegetable takes a seriously healthy food and turns it into the equivalent of a soft drink with a few vitamins. Eat your fruits and vegetables in their whole and natural form and keep your blood sugar on an even keel.

Weight Lifting And Metabolic Rate

The Study
Ninety four women were put on an 800 calorie per day weight loss diet and placed into one of 3 intervention groups: 1) Aerobic training 3 days per week for 40 minutes, 2) Resistance training 3 times per week, or 3) A control group. Fat free mass and resting energy expenditure were measured both before and after the intervention. Fat free mass is basically your muscle mass, and resting energy expenditure is the amount of calories each day your body needs to perform basic functions.  

At the end of the 6 month follow up, all of the women lost similar amounts of weight. However, the resistance training group maintained muscle mass during the weight loss period, while the aerobic exercise group and the control group lost muscle mass while losing weight. Consequently, the resistance training group had a much lower drop in resting energy expenditure after weight loss (44 calories per day) compared to the aerobic group (76 calories per day) and the control group (103 calories per day). Obesity 2008; 16:1045-51

Take Home Message
The majority of people who lose weight, eventually gain it back. A drop in resting energy expenditure is a big reason why this is the case. This study shows that a reduction in muscle mass is very likely the culprit. Muscle is a very active tissue. Each pound burns roughly 50 calories each day, whether you exercise or not. When you lose weight without weight lifting, a lot of the weight you lose is muscle and your metabolism drops. When you lift weights, you maintain the muscle and your metabolism drops much less, making it easier to keep the weight off.

If long term weight management is your goal, it is essential to hit the weights at least twice per week. You don’t need to spend hours in the gym to do this. Just do one exercise for each of the major body parts: your chest, back, shoulders, biceps, triceps, abs, and legs. The whole routine should take about 20 minutes and you can do it at home. All you need is an exercise mat and some dumbbells. Resistance training absolutely has to happen if you want to keep the weight off long term. In my opinion, it is the most overlooked aspect of weight loss programs.

Carbohydrate Quality and Depression

The Study
Almost 70,000 subjects from the Women’s Health Initiative had their diet and incidence of depression monitored for a period of 3 years. Diet was assessed at baseline by a 145 question food frequency questionnaire. Depression was assessed by means of the Burman 8 Item Scale for Depressive Disorders at baseline and at the end of the three year follow up.

Women with the highest glycemic index had a 22% increased risk of depression when compared to women with the lowest glycemic index. Similarly, women with the highest consumption of added sugars (79.2 grams per day) had a 23% higher risk of depression when compared to women with the lowest consumption of added sugars (17.8 grams per day). In other findings, dietary fiber, fruit, and vegetable consumption were each associated with a lower risk of depression, while refined grain consumption was associated with a higher risk of depression. American Journal of Clinical Nutrition 2015; 102:454-63.

Take Home Message
For many years, I have noticed that the mood of my clients improves when their blood sugar stabilizes. This investigation is the first well designed research article that backs up this theory up with good hard science.

The authors of this paper listed several possible mechanisms by which a higher glycemic index may increase risk of depression: 1) An increase in body wide inflammation. 2) Increased insulin resistance, which is associated with a pattern of cognitive deficit very similar to depression. 3) Peaks and valleys in blood sugar themselves may increase depression. 4) The counter-regulatory hormones to glucose are released in abundance with a high glycemic diet. They are cortisol, glucagon, epinephrine and growth hormone, and are associated with anxiety and depression. In order to keep a lower dietary glycemic index, choose fruits, vegetables, legumes, and whole grains over refined grains and added sugars.


Wednesday, November 11, 2015

Feature Article: Does drinking water really help you lose weight?

We have all heard that drinking a lot of water helps you lose weight. But is this just another weight loss myth that has no scientific basis, or is it really true? According to the research literature, drinking water really can make it easier to lose weight. This post will summarize some of the important research in this field of study.

Research Evidence
1) In an investigation by the Harvard School of Public Health, the long term association between water consumption and weight was examined in a combined cohort of the Nurses’ Health Study, The Nurses’ Health Study II, and the Health Professional Follow-up Study (Reference 1). In total, there were 124,988 subjects included in this investigation that were followed for approximately 20 years. Participants reported their water consumption and their weight every 4 years throughout the study period. The researchers then calculated how 1 daily cup of water would impact weight each 4 year period. 

Here are the results:
1 cup of water resulted in .3 lbs. of weight loss over 4 years.

Substituting 1 cup of water per day for 1 cup of sugar sweetened beverages resulted in a weight loss of 1.1 lbs. over 4 years.

Although the results appear modest, they do offer evidence that by increasing water consumption, you can increase your rate of weight loss. This was particularly true if the water was substituted for more calorie heavy beverages, like soda.

2) Forty-eight adults were assigned to one of two diet groups for 12 weeks (Reference 2).  The first group was assigned a low calorie diet. The second was assigned the same diet, but was instructed to drink 16 oz. of water right before each meal. At the end of the 12 weeks, the group drinking the water prior to each meal lost an additional 4.5 pounds.

3) The Stanford University A to Z weight loss trial also examined water intake and weight loss (Reference 3). This trial was designed to compare the weight loss efficacy of 4 popular diets over a year in 173 young women. In a secondary analysis, they found that women who drank more than a liter of water each day (a little more than 4 cups) lost an additional 5 lbs. after a year.

Why Does Drinking Water Increase Rate Of Weight Loss?
While we don’t know for sure, there are several potential mechanisms by which water consumption increases the rate of weight loss:

1) Increased metabolic rate. Drinking water appears to increase sympathetic nervous system activity, which increases metabolism. Calories are also utilized to warm the water to body temperature. In the research literature, drinking 16 oz of water increased metabolic rate 30% in normal weight subjects (Reference 4) and 24% in overweight subjects (Reference 5).

2) Gastric distension. Water may also increase gastric distension, which has the potential to decrease hunger and subsequent energy intake. Fifty subjects participated in a trial that compared energy intake after consuming a water preload (Reference 6).  All subjects had access to an all you can eat lunch both with and without drinking 16 oz. of water, 30 minutes before the meal. Energy consumption at the lunches were compared. The subjects over 60 years of age consumed a statistically significant 58 fewer calories after drinking the water preload. Interestingly, this was not seen in the younger subjects.

3) Water replaces beverages containing calories. If you are drinking a lot of water, then you are probably not drinking a lot of soda or juice. The elimination of these calories over time can positively impact weight.

It is clear that drinking water can have a significant influence on ability to lose weight. I have my clients shoot for 8 cups of water each day. What counts? Filtered tap water, bottled water, hot or iced decaf coffee or tea, and flavored club soda from companies like Polar, and Poland Spring.

Any beverage that is high in caffeine does not count, since caffeine is a diuretic and may cause the body to excrete water.

1) Pan A et al. Changes in water and beverage intake and long term weight changes: results from 3 prospective cohort studies. International Journal of Obesity 2013; 37:1378-85.

2) Dennis EA, et al. Water consumption increases weight loss during a hypocaloric diet intervention in middle aged and older adults. Obesity 2010; 18:300-307.

3) Stookey JD, et al. Drinking water is associated with weight loss in overweight dieting women independent of diet and activity. Obesity 2008; 16:2481-88.

4) Boschmann M, et al. Water induced thermogenesis. Journal of Clinical Endocrinology and Metabolism 2003; 88:6015-19.

5) Boschmann M, et al. Water drinking induces thermogenesis through osmosensitive mechanisms. Journal of Clinical Endocrinology and Metabolism 2007; 92:3334-37.

6) Van Wallenghen EL, et al. Pre-meal water consumption reduces meal energy intake in older but not younger subjects. Obesity 2007;93-99.


Friday, September 11, 2015

I should be using fat free salad dressings, right?

Actually, no, and for two reasons:
1) When chosen wisely, fat is a very important part of your diet. Healthy vegetable fats, like olive oil and canola oil found in salad dressings, have been associated with a reduced risk of heart disease, stroke and type 2 diabetes.

Fats also help to stabilize the blood sugar. A stable blood sugar will reduce hunger and make it much easier to lose/maintain your weight.

2) Low fat dressings are notoriously high in sugar.  In an effort to improve the taste of a dressing without fat, manufacturers add in sugar. If weight loss is your goal, sugar in your diet will spike your blood glucose and insulin levels, which promotes hunger and fat storage.

Here are some recommendations on salad dressing:
1) Skip the low fat dressings; you want a healthy fat as part of your meal.

2) Go for oil based dressings like Italian, olive oil and vinegar, or olive oil and lemon juice.

3) Avoid creamy dressing like Ranch, French, Thousand Island, Russian, etc.  These are high in saturated fat and have the potential to raise LDL cholesterol.

4) Avoid dressings like Honey Mustard and sweet vinaigrettes which are loaded with sugar.

5) Keep portions reasonable.  Oils are high in calories and it is easy to go overboard. I have my female clients shoot for 1 tablespoon of oil at a meal, which would be 2 tablespoons of oil and vinegar or Italian dressing. Men can do 1½ tablespoons of oil per meal.

Sugar sweetened beverage consumption and risk of heart disease

The Study
A randomized trial was recently published that tested whether drinking sugar sweetened beverages increases risk of heart disease. In this investigation, 85 subjects were given either 0%, 10%, 17% or 25% of energy requirements as sugar sweetened beverages for a period of two weeks. The researchers measured risk factors for heart disease both before and after the intervention. After the two weeks were over, the subjects consuming the sugar sweetened beverages had significant, linear, and dose response increases in triglycerides, LDL cholesterol, and uric acid concentrations. Subjects consuming the two higher doses of sugar also showed increases in non-HDL cholesterol, Apo lipoprotein B, and Apo lipoprotein CIII. American Journal of Clinical Nutrition 2015; 101:1144-54

Take Home Message
Years ago, sugar was considered “empty calories” that didn’t do much good, but also didn’t do much harm. That idea is changing fast. This study, and others like it, are beginning to offer proof that sugar consumption in and of itself can cause disease. The take home message here is to get sugar out of your diet entirely. If you can’t or won’t do this, do your best to strictly limit consumption. Incidentally and not surprisingly, subjects consuming the two highest does of sugar gained weight after the two week intervention.

Carbohydrate quality and long term weight gain

The Study
The glycemic load is a measure of how quickly and how severely the carbohydrate containing foods in your diet elevate your blood sugar. An interesting study was recently published that measured the impact of glycemic load on long term weight gain. Over 120,700 men and women from the Nurses’ Health Study, the Nurses’ Health Study II, and the Health Professional Follow-up Study were followed for 16-24 years. Changes in glycemic load and body weight were measured every 4 years throughout follow-up. 

There were 2 relevant findings: 1) Dietary glycemic load was independently associated with weight gain. Every four years, body weight increased .93 pounds for every 50 unit increase in glycemic load. 2) The glycemic load had a strong interaction with other foods. If a food was associated with weight gain, like red meat was in these cohorts, eating that food with high glycemic load carbs increased weight gain, while eating that food with low GL carbs decreased weight gain. The same was true for foods that were associated with reducing body weight, like plain yogurt. If high GL foods were consumed with the yogurt, the weight loss was attenuated.  If low GL foods were consumed with the yogurt, the weight loss was augmented. The American Journal of Clinical Nutrition 2015; 101:1216-24

Take Home Message
If weight loss is your goal, it is a good idea to pay attention to the glycemic load of your diet. Mechanisms by which a lower glycemic load diet promotes weight loss were discussed by the authors of this study. A higher resting energy expenditure, increased satiety, and reduced cravings with a low GL diet are all possibilities. If you want to lower the glycemic load of your diet, substitute fruits, vegetables, legumes and whole grains for bread, pasta, white rice and sugar. It is also a good idea to keep carbohydrates in the range of 45-50% of calories.