Category Archives: Fruits and Vegetables

Are There “Negative-Calorie” Foods?

Q: A “negative-calorie diet” seems too good to be true. Is it?

A: A negative-calorie diet causes you to expend more calories chewing, digesting and absorbing certain foods than the food actually contains. As an example, proponents of this diet claim that if you eat a cup of chopped lettuce that has 10 calories, you’ll burn that off and then some! While this sounds great, I haven’t found any research validating this theory. The “thermic effect of food” refers to the energy spent processing food in our system for storage and use, but we do not yet have the metabolic tools to determine this value for single food items.

Other purported negative-calorie foods include celery, carrots, cucumber, onion, spinach, apple, cranberry, orange, peach, strawberry and watermelon. The eBook The Negative Calorie Diet states that you can lose up to 14 pounds in two weeks by eating these foods! At that drastic rate, it must mean that you can only eat these foods and nothing else. But, a prolonged diet of only fruits and vegetables lacks several key nutrients, including protein and essential fats. Weight loss should always be gradual (1-2 pounds per week) and accomplished by exercising and eating smaller portions of well-balanced meals, including several daily servings of fruits and vegetables. Weight management is a delicate balance between calories in and calories out. The foods deemed “negative-calorie” are nutritious, low-energy fibrous fruits and veggies that fill you up and leave less room for higher-calorie items. If including these foods in your diet induces any weight loss, it’s likely only due to the fact that you’re eating fewer calories in general, not because your body’s digestive tract is working overtime.

Leave a comment

Filed under Fruits and Vegetables, Heart Healthy Choices, Weight loss

The Big Deal About “Organic”

Q: Is organic food more nutritious?

A: Not necessarily. The term “organic” is defined by the USDA. Organic meat, poultry, eggs and dairy must come from animals given no antibiotics or growth hormones. Plant foods (e.g. fruits, vegetables,  grains, legumes) must be produced without pesticides, artificial fertilizers, genetic modification or  irradiation. The government inspects every organic farm to make sure it meets these standards. There  are three levels of organic food claims:


100% Organic:Products that are completely organic and are produced organically at every step. For example, in a 100% organic trail mix, all the nuts, raisins and granola must come from organic fields and be processed in organic factories.

Organic: At least 95% of a product’s ingredients meet organic standards.

Made with Organic: At least 70% of a product’s components are organic. (If a product contains less than 70% organic ingredients, the USDA forbids the use of the word “organic” on the label.)

Organic agricultural principles are kinder to nature and to farm animals, but are organic foods healthier? The jury is still out. In March 2008, The Organic Center completed a review of scientific research and found that organic plant-foods are more nutritious, on average, than conventional foods. In contrast, a September 2009 study funded by the UK Food Standards Agency and published in the American Journal of Clinical Nutrition found no evidence of significant differences in nutrient quality between organically and conventionally produced foods (Dangour, et al). Until research is more conclusive, non-organic foods have the same nutritious components – vitamins and minerals included – as organic items. The difference lies in growing practices.

I realize buying everything organic is nearly impossible and can get very expensive. Here are 5 tips:

1. Buy dairy products free of artificial hormones, which force increased milk production in cows.  The health risk to humans is controversial, but recombinant bovine growth hormone (rBGH) has been banned in the European Union for over 15 years. “Hormone-free” milk is not hard to find (you may already be drinking it!) and does not cost a lot.

2. If it’s a fruit or vegetable that you eat without peeling first, such as grapes or celery, think about buying the organic version. On the other hand, when you remove a thick skin off produce (like on an orange or banana), you reduce consumption of the chemicals used during farming and production anyway.

3. If the fruit is prone to soaking up a lot of chemicals during farming, buy organic. For example, non-organic berries and thin-skinned peaches are likely to retain a lot of chemicals, even after washing.

4. Due to body size, chemicals are more toxic to children. The government deems pesticides “safe” when used within certain restrictions, but it is especially important to limit a developing baby’s or child’s exposure to potentially harmful chemicals.

5. Always thoroughly wash your fruits and vegetables under running water! This can remove dirt particles, as well as some of the remaining pesticide or fertilizer used on non-organic produce.

Leave a comment

Filed under Dairy, Food Groups, Fruits and Vegetables

Protecting your heart

Q: My doctor says I have high cholesterol. What can I do to lower it?

A: There are several components to a “lipid profile” – total cholesterol, LDL (“bad”) cholesterol, HDL (“good”) cholesterol and triglycerides. If your physician is telling you that you have “high cholesterol,” he is referring to either the total cholesterol number, your LDL reading or both. A desirable profile is as follows:

Total cholesterol <200 mg/dl

LDL cholesterol <130 mg/dl

HDL cholesterol >40 mg/dl (>50 mg/dl for women)

Triglyceride level <150 mg/dl

Cholesterol is a component of animal products and is not found in plant-based foods. It is necessary in the body for the production of bile, which helps digest fats, and steroid hormones (e.g. vitamin D, estrogen and testosterone). While the body utilizes cholesterol for important functions, the liver is also able to synthesize necessary amounts – it is not necessary to ingest it as part of your diet! Total cholesterol, LDL and triglyceride levels that are too high put you at risk for cardiovascular disease.


Let’s focus on LDL cholesterol, since it has been linked to atherosclerosis, coronary heart disease, heart attack and stroke. Several factors influence LDL levels, including age, diabetes, obesity, reduced estrogen levels and diet.  Diets high in saturated fat and cholesterol elevate LDL. In addition, trans-fats can raise LDL and lower HDL (“good”) cholesterol – a double whammy!

Lower your saturated fat intake! Saturated fat intake has a much greater negative effect on blood cholesterol than does dietary cholesterol. (Dietary cholesterol, however, is often found in the same foods that are high in saturated fat.) Choose lean meats, select skim milk, low-fat dairy products and stick to vegetable oils that are liquid at room temperature (e.g. cook with olive or canola oil, rather than butter or lard.) To further cut back on fat intake, remove the skin from chicken before eating, substitute margarine for butter and grill or bake fish, meat and poultry instead of frying.

Eat a minimum amount of trans-fat. Select products that are made with no hydrogenated (or partially hydrogenated) vegetable oils. Check the ingredient list before buying!!

Lastly, up your intake of viscous or soluble fiber. Choose more fruits, vegetables, beans and whole grains, especially barley and oats.

While there are several ways to manage blood cholesterol levels with medication, try modifying your diet first. Just a 1-point decrease in your LDL cholesterol level corresponds to a 1-2% decrease in your risk for developing coronary heart disease!

7 Comments

Filed under Fruits and Vegetables, Grains, Heart Healthy Choices, Medical Conditions

Grapefruit-Medication Interactions

Q: I heard grapefruit interacts with certain medications. Is this true?

A: Yes. Unlike other citrus fruits, grapefruit interferes with the metabolism of a few dozen drugs (see partial list below). A chemical component within the fruit prohibits a certain digestive enzyme in the body from breaking down these medications. By continuing to consume grapefruit or grapefruit juice, you decrease the efficacy of the medication you’re on, and the drug itself can build up to dangerously high levels in the blood. Grapefruit should be fully avoided, as its effects wear off very slowly and are still evident 24 hours after consumption. Separating medicine and grapefruit by several hours will not prevent the drug-nutrient interaction. Having grapefruit once accidentally, most likely, will do no harm, but it’s advisable to switch to another type of fruit or fruit juice. The National Institutes of Health recommends not making any sudden diet changes, however, if you’ve always taken your medication with grapefruit. Speak to your doctor first, as your body may be accustomed to a certain level of the drug in your blood.

Avoid grapefruit and grapefruit products when taking the following:

  • The high blood pressure/angina drugs Plendil and Procardia/Adalat
  • The cholesterol-lowering agents Zocor, Lipitor and Mevacor
  • The immunosuppressant medications Sandimmune and Rapamune
  • The anti-anxiety/anti-insomnia drugs Valium, Halcion and Versed
  • The neurological medications BuSpar, Zoloft and Tegretol

Note: This is not a complete list of medications that interact with grapefruit. Always check with your physician and/or pharmacist.

Leave a comment

Filed under Fruits and Vegetables, Medical Conditions

Benefits of Fiber

Q: What exactly is ‘fiber’ and why is it so good for you?

A: Fiber is an indigestible carbohydrate, or a string of sugar units held together by bonds that human digestive enzymes cannot break. There are two types: soluble and insoluble fiber.

Food Sources

Soluble fiber: barley, oats, oat bran, rye, fruits (especially apples and citrus), beans, vegetables, seeds

Insoluble fiber: Brown rice, fruits, beans, seeds, vegetables (cabbage, carrots, brussels sprouts), wheat bran, whole grains

While fiber does not provide energy, it has many other beneficial effects:

1. Lowers blood cholesterol: Soluble fiber reduces cholesterol and the risk of heart disease by several mechanisms. (Note: This is why General Mills is able to claim that eating whole grain oat Cheerios can help lower your cholesterol.)

2. Maintains bowel function: Insoluble fiber speeds up the transit of food through your system, while soluble fiber slows it down.

3. Assists blood glucose control: Soluble fiber slows the absorption of glucose from the intestine into the blood stream, thereby preventing a spike (and crash) in blood glucose after a meal. This can lower the risk of type 2 diabetes.

4. Promotes weight management: Fiber makes you feel full and lessens hunger

5. May defend against colon and rectal cancer: Scientific studies are mixed, but insoluble fiber speeds up the removal of cancer-causing agents from the colon, while resident bacteria in the colon ferment soluble fiber, producing a beneficial compound that may help colon cells resist injury.

Recommended Intake: Since most fiber-rich foods supply a mixture of soluble and insoluble fiber, recommendations are given without regard to type. The American Dietetic Association suggests 20 – 35 grams of fiber daily, which is about twice the average intake. That said, don’t overload on fiber and make sure to increase fluid consumption as you gradually increase fiber intake.

Fruits, vegetables, whole grains and beans are among the best sources of fiber! Also, remember that fiber supplements are not necessarily substitutes for whole, fiber-rich foods.

Check the nutrition facts on the back of products to find out how much fiber is in one serving! Here are some examples:

½ cup whole grain barley – 3g fiber

½ cup instant oatmeal – 2g fiber

1 slice whole wheat bread – 3g fiber

1 slice white bread – 1g fiber

½ cup cooked brown rice – 2g fiber

½ cup cooked white rice – less than 1g fiber

¾ cup (2 oz) whole wheat penne pasta, dry – 6g fiber

¾ cup (2 oz) regular penne pasta, dry – 2g fiber


1 medium apple (with skin) – 3g fiber

1 medium pear (with skin) – 5g fiber

½ cup blackberries – 4g fiber

½ cup strawberries – 2g fiber

1 medium orange – 4g fiber

½ cup orange juice – less than 1g fiber

½ cup American grapes – less than 1g fiber


½ cup lentils – 8g fiber

½ cup chickpeas (garbanzo beans) – 5g fiber

½ cup black beans – 7.5g fiber


½ cup cooked broccoli – 2.5g fiber

1 medium artichoke – 10g fiber

1 medium baked potato (with skin) – 4.5g fiber

7 Comments

Filed under Fruits and Vegetables, Grains, Heart Healthy Choices, Medical Conditions, Weight loss