Whole Fruit vs. Blended Fruit

Surely you know that smoothies are better for you than juices because they retain the fiber content of the fruit/vegetable, but have you asked yourself if a fruit smoothie has the same effect on your body as whole fruit? The answer may surprise you!


This question came up today because a friend of mine has been on Weight Watchers for the past few months, and she was recently switched from PointsPlus to the new SmartPoints program. Under PointsPlus, most fruits and vegetables counted as zero point foods. With the updated points system, whole fruit is still zero points, but blended fruit (i.e. fruit in smoothies) has a SmartPoints value.

My friend said she and everyone else at her Weight Watchers meeting were very frustrated at this change. After all, fruit in a smoothie still technically contains the whole fruit! What gives?

If you’ve been wondering the same thing, I tried to dig up some science to explain it. It surprised me that there isn’t more evidence available documenting the effect of blending a food on glycemic index, satiety, and nutrient absorption. Here’s what I found, though:

  1. A 2007 study published in the International Journal of Obesity studied the effect of liquid meals vs. solid meals on satiety. The results showed that participants consumed on average 12% more calories per day when drinking a carbohydrate-rich drink. This suggests that drinking a blended fruit smoothie is less filling than eating a calorically equivalent portion of fruit. This is likely attributed to the fact that eating fruit takes longer than drinking it. Satiety signals are released as a hormones from the gut, and these must circulate through the bloodstream to your brain before you realize you’re full. That’s why waiting 15-20 minutes after eating a meal before deciding to eat a second helping is a good practice to adopt to avoid overeating.
  2. Chewing increases satiety. This has been documented in a study published in The British Journal of Nutrition in 2013. More chewing led to an increase in secretion of CCK in the gut (hormone that decreases appetite) and decreased secretion of ghrelin (hormone that increases appetite).
  3. Blending fruit changes the insoluble fiber contained in it. While it’s not accurate to say that blending fruit “destroys” the fiber, it does “change” it by breaking it into smaller particles. When you break the fiber compounds into smaller pieces, different things can happen, as explained in The Journal of Food Science article here. This is where the science gets sparse. Robert Lustig, MD, professor of pediatrics at University of California, suggests that blending fruit fiber has a negative effect on the glycemic index of foods. “The blades destroy the insoluble fiber, which means that the ‘gel’ that forms on the inside of the intestine has no structure. The sugar is absorbed at a maximal rate, overwhelming the liver’s capacity to metabolize the sugar, and the excess sugar is turned into liver fat which is the precursor to metabolic syndrome.” (Quote from Time magazine article April, 2015) That sounds reasonable to me, but I would much prefer a peer reviewed article cited to back that claim up!
    **If you want to completely nerd out over the food science of stuff that affects glycemic index, read this as well.

These factors combined help to explain why eating the whole, unprocessed version of a food is more filling than eating a blended, juiced, or puffed version of it. This also helps to explain why pureed or blended fruits have SmartPoints under the new Weight Watchers program. I hope that helps clear things up! Hit me up in the comments if you’d like to see more questions like this answered in the future.


International Journal of Obesity (2007) 31, 1688–1695; doi:10.1038/sj.ijo.0803667; published online 19 June 2007

Zhu Y, Hsu WH & Hollis JH (2013). Increasing the number of masticatory cycles is associated with reduced appetite and altered postprandial plasma concentrations of gut hormones, insulin and glucose. British Journal of Nutrition 110: 384–390.

Weight Watchers Review

Yes, I’m a Registered Dietitian and I signed up for Weight Watchers this year. The company was running a promotion and lots of awesome commercials around Super Bowl Sunday. They had just rolled out a new program, Personal Coaching, which matches you up with an accountability partner who you can call, email, or text whenever you’re struggling with making a healthy food choice. The personal coaches are all people who have successfully lost weight and kept it off for years using the Weight Watchers program.

Weight Watchers has been ranked the top commercial weight loss program on US News’ annual report for the past several years! Experts agree that it encourages healthy eating habits and its long term success is fairly well documented.

This may come as a shock to you, but even Registered Dietitians struggle with their weight sometimes. My weight has always fluctuated, and in February I found myself looking and feeling less than my best. I was about 10 pounds heavier than I like to be and was struggling with overeating junk foods. The timing was perfect because Weight Watchers was offering a money back guarantee to anyone who tries the program and successfully loses 10 pounds in 2 months. I took some (unflattering) before pictures and signed up!

The first thing I did was fill out a questionnaire. The survey basically asked about my eating habits, who I live with, and what aspects of eating I struggle with the most. I initially thought it was a very helpful assessment, but later discovered that it is just used as a tool to help the coach get you started. Over time, my plan evolved away from my initial responses to the questions.

I was put on 26 points per day, with 49 bonus points available per week to splurge on additional foods. I picked my coach off a list of people suggested for me. My coach, Cheri M., described herself as someone who would be my cheerleader and accountability partner. I loved the energy she portrayed in her profile, and I’m so glad I picked her!

Two months, 8 or 9 phone calls, and about a dozen emails later, I was down 10 pounds and keeping them off! I stayed signed up for an additional month to learn about Weight Watchers maintenance techniques. In the maintenance phase my daily points increased to 32 instead of 26 and I still had my 49 bonus points per day. I started out weighing 138 lbs and ended up 128 lbs at 5’3” and 27 years old.  I am no longer using Weight Watchers, but I would recommend this program to adults wanting to lose weight.

If you’re considering Weight Watchers’ Personal Coaching program, here are some pros and cons I’ve come up with:


  1. Incentives! I liked being motivated by getting my money back. At almost $60 per month, the personal coaching program wasn’t excessively expensive, but $120 is enough money to buy some cute new workout clothes, a massage, or a few pedicures!  I was determined to succeed so I could prove to myself I could do it and get that money back to treat myself to something nice.
  2. You can eat anything! Weight Watchers counts points, and you get a certain number of points per day. I was given 26 Points Plus per day to use on whatever foods I wanted. Obviously, it makes more sense to eat a lot of low point foods to feel more satisfied, but not having any foods “off limits” made it a lot more manageable to stick with the plan.
  3. Emphasis on fruits and vegetables. Fruits and vegetables have zero Points Plus! That means that (most) fruits and vegetables are “free foods.” Whenever I was hungry between meals or wanted to make a meal more filling, the best strategy was to munch on fruit or pile a sandwich high with vegetables. I was a little concerned that I wouldn’t lose weight because I was eating so much more fruit than usual, but the weight still came off. It really is true that it’s very difficult to gain weight from eating too much fruit.
  4. Weekly bonus points and activity points! I was given 49 extra points each week to use if I wanted to splurge a little. Typically, I would use most of those points on a single day, but sometimes it was helpful to have a couple extra points available each day. You earn activity points by engaging in physical activity and can use those extra points on food, too. You even get a choice of letting the activity points “rollover” from day to day or have them expire at the end of each day. Thinking of points as food currency was a good mental trick for budgeting my calories better.
    WW Screenshot 2
  5. Weekly weigh ins and reset. Some weeks I went over my Points Plus allowance, even with the weekly bonus points and activity points. It would have been discouraging to see that failure follow me for weeks, but the nice thing is that all your weekly bonus points reset once per week! It was good for me mentally to have the slate wiped clean. Weighing once a week was nice, too. I chose Wednesdays for my weigh in day since some studies have suggested that’s the day of the week people typically weigh the least. Once a week was enough to hold me accountable, but also keep me from obsessing over small fluctuations in weight.
    WW Screenshot 1
  6. The website. Weight Watchers’ website has lots of great tools, including “cheat sheets” and videos to help you choose low point options at the bar and restaurants. They even have tutorials for learning how to estimate Points Plus in foods when the nutrition information is not available.
    WW Cheat SheetsWW Cheat Sheet Cocktails
  7. My coach! My faaaavorite aspect of the Weight Watchers personal coaching program was my personal coach, Cheri M. She was absolutely wonderful. We had a phone call to talk about progress and plan for the upcoming week on my weigh in day each Wednesday. Cheri always started the conversation by asking me what went really well that week and then cheered me on to keep it up. We would then spend a few minutes thinking ahead to the coming week to plan for upcoming challenges or address difficult patterns I was falling into. Cheri shared some really great, creative ideas with me that I was able to get very excited about! For example, when Colby and I went out of town for the weekend, she asked me to first consider how I wanted to feel when I came back from the trip and then establish what choices I would have control over on the trip to feel that way when I got back. It really helped to keep my food choices in check while we were traveling to San Francisco; I was able to enjoy some treats, but came back feeling energized and proud instead of bloated and full of remorse. In addition to the wealth of helpful information, Cheri wrote “action plans” for me each week. The action plan was typically a three part commitment for the upcoming week. Here’s an example of one of my action plans:
    1. I will pre-track my breakfast and lunch each day (Monday-Friday) before work.
    2. I will be in bed by 9pm Sunday-Thursday and by 10pm Friday-Saturday.
    3. I will pack a lunchbox full of snacks I can graze on throughout the day on Saturday and Sunday.
  8. It actually works! I lost 10 pounds in 2 months and got my money back! I’m still keeping it off. Once I lost the weight, my daily Points Plus increased to 32 per day. For each week of maintenance, if I was able to keep my weight within 2 lbs of my goal weight, my daily Points Plus stayed at 32 and I still got my 49 weekly bonus points. Even though I’m no longer paying for Weight Watchers, I feel like I learned some helpful strategies and healthy habits from the process.


  1. Limited database. The food and activity database on the Weight Watchers tracker is limited. The database on MyFitnessPal contains faaaaar more foods and exercises, which makes tracking easier than it is with the Weight Watchers tool. Here is a comparison:
    WW food not foundMyFitnessPal food found
    The activity database had some hilarious entries! I’m sure that using an activity tracker would have been much more useful for estimating energy expenditure than these options:
    WW Screenshot Activity
  2. Questionable food choices. To keep Points Plus values down, I sometimes chose more heavily processed low fat foods instead of more wholesome, higher Points Plus value foods. For example, I switched from whole grain bread (3 points per slice) to Sara Lee 45 calorie 100% Whole Wheat bread (3 points per TWO slices). The latter contains more ingredients. This wasn’t true for everything, though. I tried fat free cheese for the first time (gross), and ultimately decided to stick with very thin sliced full fat cheese for my breakfast sandwiches to keep Points Plus values low.
  3. Redundancy. Ultimately, I got bored with the program. My coach’s ideas were fresh and exciting at first, but after three months of weekly follow ups, I started to feel like I wasn’t learning anything new and that spark of excitement kindof died. I’m sure this is what happens when I meet with my patients, too. After following up with a dietitian or nutritionist several times, it’s easy to feel like you’ve heard it all and lose interest. I think part of the key to keeping weight off is to stick with the healthy habits you built while losing weight and keeping yourself in check. If you notice the weight start to creep back on, strive to find ways to get excited about losing those couple of pounds again! I’ll write another post specifically about that sometime.

What questions do you have about the Weight Watchers program? If you’ve used the program before, what was your experience with it?