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My 3 Day Tube Feed Formula Diet

It was Feeding Tube Awareness Week from February 10th to 14th, 2020, and I decided that I wanted to do something big to enhance my tube feeding knowledge and raise tube feeding awareness in my community.

ingredients in tube feed formula Boost Ensure Isosource Jevity
The typical ingredients in tube feeding formula. This photo represents the ingredients in a single serving (250 mL) of the formula I consumed for 3 days.

Tube Feeding Without a Feeding Tube?

I seriously considered having a nasogastric feeding tube inserted into myself, in order to try being tube fed. In the end, I decided against that option and instead opted to experience just one aspect of tube feeding, having a diet of only tube feeding formula and water for 3 days.

I felt that this would help me better understand what it’s like to be tube fed. Why tube feed formula and not my own blended meal recipes? Well, tube feeding formula remains the most commonly prescribed nutrition for tube fed people. In fact, there are many tube fed people who are given no choice but to use formula for their nutrition and are not supported whatsoever in exploring more natural options. Plus, in the hospital setting, there can be policies against the use of blended food for tube feeding and many clinicians have only had training on the use of formula. So, a diet solely of tube feeding formula is the most common tube feeding experience and seemed like the most appropriate way for me to challenge myself to take a huge step away from my usual diet, learn something about what it may feel like to be tube fed, and raise awareness of tube feeding.  Of course I understand that this experience would in no way be the same as being actually tube fed, but it was the closest thing I could manage.

Assessing my Nutrition Needs for Tube Feeding

The first thing I did was assess my nutritional requirements exactly as I would for a tube fed patient. Keep in mind that I work at a major acute care hospital in Vancouver, Canada and have been conducting tube feeding assessments on a daily basis for 15 years. Based on my height, weight, age, and gender, my resting energy requirement would be 1479 calories. As I anticipated my physical activity to be minimal during the three day period, I used an activity factor of 1.3. This meant my overall nutritional need would be 1923 calories per day.

Choosing my Tube Feeding Formula

I decided that a 1.5 calorie per mL fibre free formula would be the most suitable choice for my diet. I could meet my nutritional needs in about 5 boxes per day which would provide 1875 calories and 85 grams of protein. Why fibre free? Well, I wanted to experience the dietary change that many tube fed adults go through. In many cases, before requiring tube feeding they would probably be eating their usual varied diet of whatever foods they enjoy. Their usual diet could be high in fibre. Then, they have a health problem that necessitates tube feeding and are prescribed a fibre free formula.

In hospitals, a fibre free formula is often used as an initial formula prescription for adult tube fed patients. Sometimes it’s never adjusted to a fibre containing formula. Also, there are some formulas that do not have a fibre containing option (renal formulas for example). In the home setting, fibre formulas are much more expensive than fibre free options, so many people will not have the option for fibre formula if their insurance doesn’t cover the cost of their formula.

Tube Feeding Formula without Fibre

I wanted to see what would happen to me if I suddenly went from my usual high fibre diet, to a diet devoid of fibre. So, I went ahead and stopped by a local medical supply store and purchased a 24 case of 250ml boxes of 1.5 calorie fibre free formula. Below I describe my experience consuming only tube feeding formula and water for 3 days. It is my personal experience and not necessarily reflective of anyone else's experience on a tube feed formula diet. Also, I realize that this was in no way a true tube feeding experience as I am a healthy person voluntarily drinking tube feeding formula. I didn't even have an actual feeding tube.


Tube Feeding Formula Challenge- Day 1

My tube feeding formula challenge started on February 10th which was a Monday and a work day for me at the hospital. I tasted the formula for the first time on Monday morning when I intended to drink my breakfast box of formula. I planned on drinking the five boxes spread out over the course of the day.

The taste was not good. Why would it be? This was a tube feeding formula intended for tube feeding, not for drinking. That said, the taste was not terrible. It wasn’t as sweet as I expected and seemed to have a mild vanilla flavour and a very creamy mouth feel, which I liked. There was a somewhat unpleasant aftertaste which was probably due to the added vitamins and minerals. My initial impression was that I was going to have a hard time drinking the five boxes a day, due to the relatively unpleasant overall taste experience.

Things began to get interesting right away on Monday. When I got to work I missed my usual morning coffee. Not having caffeine wasn’t a problem, and I realized that for me, my morning coffee is more about enjoying a quiet moment with a hot drink at my desk. It warms me up and is something I look forward to at the hospital each morning. This gave me immediate insight into the losses involved when a person can’t eat and needs tube feeding. The loss of a morning coffee is perhaps a small thing in the grand scheme of things, but my heart goes out to people who don’t have the option to partake in food focused rituals.

Back to my day… I went straight to my units to do my usual patient care routines. Only about an hour after “breakfast”, I was getting very hungry. I ended up going to my office at 10 am to have my second box of the day. I drank it quite quickly due to being short on time and felt mild nausea afterwards. The feeling was somewhat familiar. The best way I can describe it is that it felt like I had eaten a huge bowl of ice cream. I felt mildly nauseous and very very thirsty afterwards and had a strong urge to drink a large volume of water.

The thirst and mild upset stomach can, I think, be explained by the relatively large amount of sugar in tube feeding formula. This was a 1.5 calorie per mL product, which is quite concentrated and therefore especially high in sugar. I think the large amount of sugar made me feel sick and the thirst was my body telling me that I needed to drink water to dilute the concentration of sugar in my stomach.

Tube Feed Formula Ingredients

I think that at this point, it’s important for me to explain the ingredients in my formula tube fed diet. In a box of a 1.5 cal/mL fibre free formula, there is quite a lot of sugar as you can see represented by sugar cubes in the photo below. Technically the sugar in my formula wasn’t table sugar, it was corn syrup and corn maltodextrin. Both are sugar nevertheless, and very high on the glycemic index scale. This means that you absorb these sugars very very quickly. My usual diet is low in sugar, so I think my body wasn’t prepared for this sudden dramatic change. We often see sugar cubes used to represent the sugar content of common foods and beverages. I calculated that each box of my tube feeding formula is equivalent to about 11 sugar cubes.

Tube Feeding Formula Ingredients: Sugar, Oil, Water, Electrolytes, protein powder, vitamins and minerals

The other ingredients are water, oil, protein, vitamins, minerals and electrolytes, (plus preservatives, emulsifiers etc). No fibre, like I explained above. I must say that I was very worried about my intestinal microbiome. A healthy microbiome supports a healthy body. The intestinal microbiome refers to the trillions of microorganisms that live happily in our gastrointestinal tract. I think I have a good mix as I rarely get sick and have maintained a healthy digestive system for my whole life. I typically consume large amounts of fruits and vegetables which provide lots of indigestible fibres which feed and support the microbiome. On my usual diet I do have some bloating after meals which is certainly due to the production of gas from the metabolism of my microbiome organisms. Without diverse plant fibres, I worried about the health of my microbiome. Would the bacteria die because they weren’t going to receive their preferred energy source (plant fibres)? A diverse diet is consistently associated with a diverse microbiome -- a good thing-- but tube fed diets of only standard formula do not have any diversity. I worry about the effect on the microbiome of tube fed patients who never have any whole foods in their diet.

I’ll carry on with recounting my first day on the tube feed formula challenge. The main finding on day one was hunger. The hunger was almost constant. I would drink the formula and have a degree of satiation, but within an hour or less, I’d feel as hungry as ever. I wasn’t expecting this. I also was surprised to find that I had to sip the formula very slowly and aim to finish a box in about 30 minutes. Any faster and I would feel that mild nausea/upset stomach. This also really surprised me and made me question the tolerability of tube feed formula. I always perceived 1.5 calorie per mL formula to be not particularly concentrated but now I see it differently, I think it is perhaps harder to tolerate than a less concentrated formula. I also think that a 2 cal/mL formula would be really challenging to tolerate personally and this has made me question whether it’s a good option for my tube fed patients.

Already, after just one day on my tube feed formula diet, I had learned a lot. In my usual practice, I always ask my patients if they are hungry or thirsty. Some people will say that they are neither hungry or thirsty, even if I know that they are recieving no where near enough nutrition and hydration. Meanwhile, some people will say that they are hungry or thirsty every time I ask them, even after I’ve made significant increases to their formula and flushes. I would like to mention that I like to offer my patients the option of a blended food formula in hospital and I also offer the option of using blended food and fluids from our pureed diet. For those receiving our pureed diet, they receive a meal tray at breakfast, lunch and dinner. I have noticed that those patients seem to be satisfied with less calories probably because their brain actually knows that they ate a meal because they saw and smelled the food. That’s a very different experience from being tube fed formula.

Tube Feeding Formula Challenge- Day 2

On day 2 on my formula diet, the hunger was overwhelming. I had already decided that I would have to go up to 6 boxes of formula (2250 calories, 32 calories per Kg). I assumed that I had underestimated my nutrition needs which was why I had been so terribly hungry on Day 1. Day 2 was particularly challenging because there was a “staff appreciation” lunch at the hospital. It’s not often that a free lunch comes along and this one was generously provided by my manager. I realized that it was going to be a challenging situation for me to go to the lunch but not eat any of the food. I could have brought a box of formula to the lunch, but to be honest, I was self conscious about doing that and decided to drink the formula beforehand and then go to the lunch just for the social experience.

It was a difficult experience for me because I was very very hungry and I was surrounded by food. It was also a little strange to not be eating when everyone else was. Again, this was an opportunity for me to reflect on the experiences of tube fed people. So many social gatherings are food focused. If you’re tube fed, these situations could be really hard. I was open with people about why I wasn’t eating (this was an opportunity to help spread tube feeding awareness) and some people said that they didn’t want to eat in front of me because they felt sorry for me. This was in no way my intention, but I could understand why they feel that way. I know that I personally would probably not feel comfortable eating in front of a tube fed person, but eating is a part of daily life and for people living with tube fed loved ones, they should feel free to eat as usual.

Anyway, after lunch my day continued more or less uneventfully but overshadowed by hunger. I also began to realize that I was getting irritable and was having a hard time focusing. These are problems that I am aware of when I am hungry. The odd thing about this situation was that I knew that I was getting plenty of calories. I shouldn’t be hungry based on the fact that I was now on track for 6 boxes over the course of the day. Again, I have to go back to the sugar content of the formula. I think that it’s possible that I was absorbing the sugar really quickly since it’s in liquid form and highly digestible, but the energy wasn’t sustained. In other words, I was probably having a sugar high (although I never felt a surge of energy), followed by a low shortly after. In other words, even though I was drinking the formula, it didn’t satisfy my hunger.

I also was seriously considering that a big portion of the hunger was psychological because I wasn’t eating food like I usually would, my brain was refusing to register that I had taken in any nutrition. On Instagram I was sharing my experience and my thoughts about this and I received an interesting comment from a geriatric dietitian. She said that there have been studies of people with severe dementia where they bring them to a table and tell them it’s time for a meal. The people eat their full portions of food. Then, an hour later, they will bring them back to the table and tell them again that it’s time to eat. Since these people can’t remember that they had just eaten, they will eat the meal again. So, fullness isn’t just about having food in your stomach, there is something more to it. For me, maybe the tube feeding formula wasn’t registering with my brain as me having eaten a meal. It makes me wonder if there’s more we can do to enhance the meal times of tube fed people. I personally believe that tube fed people should come to the dining table, see and smell their meal (hopefully it’s fragrant and attractive) and experience the social benefits of sharing a meal with other people.

So at the end of day 2, the hunger was the main challenge, the brain fog was setting in (difficulty focusing) and I was counting down to the finish line. Even immediately after drinking box of formula, I felt like I could eat a full meal. It took all my self control not to cheat and eat something "real". My mood wasn’t great. My energy was low and I was irritable. I believe I can attribute these feelings to my diet change. The other interesting thing was that I hadn’t had a bowel movement. I also had absolutely no abdominal bloating and had passed gas only once in 2 days. This seems very odd to me and again, I worried about the health of my intestinal microbiome. I also decided that because of the hunger which was all-consuming at that point, I would up my formula intake to 7 boxes for the 3rd day of the challenge.

Tube Feeding Formula Challenge- Day 3

So. Day 3. I was not feeling good when I woke up. Very low energy and immediate hunger. Interestingly, I was excited to drink the formula because I was so hungry. Also, the formula seemed to taste better and I can honestly say that I enjoyed drinking it. Again, I have to attribute this to the intense hunger. I would have eaten, and probably enjoyed, anything.

Off I went to work and did my best to conduct my duties to the highest standard. This was surprisingly difficult. My thoughts were fuzzy, I didn’t feel mentally sharp and I found myself feeling a little lost. This is not at all how I usually feel. For example, I felt the need to triple check all of my clinical calculations. Also, things took longer than usual. I paged a doctor for a verbal order for a patient and after I got off the phone, I promptly forgot the doctor’s name. This was quite embarrassing because I had to call back to get his name. I also needed to go pick up a new set of scrubs from the human resources department. When I got to the dept door, it was locked. It took me a long time to figure out that I had to call in to get someone to come to the door. I could not remember the name of the contact person and stood staring at the directory for several minutes before someone came along and pointed out a huge sign right next to me that said “Picking up work clothing? Call this number:”. I hadn't noticed the giant sign that explained exactly what to do to get my scrubs.

At that point I was really feeling like I needed to stop the diet and eat “real food”, but I pressed on. It was a big challenge to finish out the 3rd day. I had very low energy but had no choice but to get through my work day and then head home to prepare for house guests who were arriving that night. I tried to sum up my thoughts for my social media and had difficulty writing without making typos. It seems harder than usual to express my thoughts. Oh, the big news of the day was that I finally had a bowel movement on day 3! It was very strange in appearance but it wasn’t diarrhea. I won’t get into all the details, but it was quite foreign to me and best described as "smooth". Also, there was still no bloating whatsoever and I think that now at 3 days in, I had only passed gas twice.

There were some positive elements to the tube feed formula diet. The biggest was convenience. All I had to do was open the box and drink the formula. No meal planning, no cooking, no cleaning. I had a lot more free time because usually I spend at least an hour and a half cooking, eating and cleaning up our dinner meal. This experience also made me realize that those “chores” are also a blessing. I would miss cooking and meal planning if I couldn’t do it anymore, and I know that tube fed adults are attracted to blenderized tube feeding for that exact reason. They want to get back into the kitchen and cook. They want to have a choice in what goes into their diet.

It was also quite useful to not have to worry about food safety. I could take a box or two of formula on the go in a bag, no need for refrigeration. I didn’t go anywhere near my fridge during the 3 day period. There was no reason to.


After 3 Days on a Diet of Tube Feeding Formula

I learned a lot from this experience. The biggest challenge was definitely hunger. Increasing my calorie intake did not help. This surprised me. On day 3 I had 7 boxes of formula which provided me with 2625 calories, 119 g protein today (If you’re a dietitian reading this, for reference that is REE x 1.7, 38 cal/kg, 1.7 g pro/kg!). Despite this very large calorie intake, I still felt hungry all day. This makes me very worried that there are tube fed people who may be feeling hungry, but can’t communicate this (non-verbal children, adults with reduced cognitive function or expressive aphasia). I think that blended food would be a more satisfying option than standard formula, because it’s thicker and can be made with foods containing fibre and complex carbohydrates instead of sugar. I believe that due to the same reasons, blended food is better tolerated- it’s not so concentrated and high in added sugar. I really had a hard time (nausea) if I drank the formula quickly.

The thirst was another surprise. It was not as bad as the hunger because I could relieve the feeling by drinking water. I drank water very frequently and always right after taking in the formula. I cannot imagine being limited to only a small volume of water before and after each meal as we so typically order for fluid-restricted tube fed patients. I think not having control over my fluid intake would have reduced my ability to tolerate the formula because it would have been harder to drink due to the richness and concentration sugar. I tracked my water intake on day 3 and can report that I drank over 3 litres (this was me drinking “to thirst” not deliberately trying to drink a lot). If I count the fluid from the formula and the water,  I’d estimate my fluid intake was 5 litres on day 3. (RDs that’s 70 mL/kg….way more than I have ever ordered for any adult tube fed patient in my whole career). This really surprises me and makes me really feel for tube fed patients who can’t respond to their thirst by taking in more water.

Finally, although this was a major change to my usual diet and I consumed a very large amount of sugar (equivalent to 198 sugar cubes in 3 days!), I was ok. Did I feel great? No, but for the short term, I know that I technically had my nutritional needs met. It’s no secret that I’m a big advocate for blended diets for tube feeding. In fact, this is my passion and naturally, the subject of my research and the focus of my career. I believe that every tube fed person should be offered the choice of formula, food based formula, blended food, or any combination of the three. Diet needs to be individualized for tube feeding, just like for people to eat by mouth, and tube fed diets should reflect personal dietary preferences. Find what works for you, the tube fed person, whether that’s formula or blended food.

I have a new appreciation for simply being able to eat. When I did finally eat again after this challenge ended, I savoured every bite and devoured the meal with a smile on my face. I want every tube fed person to experience that great feeling and my heart goes out to the tube fed people who miss eating but are not able to eat again due to medical reasons. Through this experience I have increased my understanding of the challenges of being tube fed. I've shared so many tube feeding stories on this blog and this is quite odd to be sharing my own story. Of course there is no comparison to actually being tube fed, but as a clinical dietitian who works with tube fed people every day, I gained new insight and understanding into what it's like and I will apply these new learnings to my practice and hopefully become a better care provider.

Thank you for reading!




I have a unflavored formula called nutren and it tastes like a medical meal and my best solution was liquid creamer. My favorite is pumpkin spice because it has a very strong taste


Nov 30, 2022

Wow, thank you for this.

I have been tube feeding my wife now for just over a year. ( she has MS and can no longer swallow properly) She also has a lot of trouble speaking so communication is minimal. I try different things to help her enjoy meals and I stopped eating around her so she doesn't have to smell food.

Your observations have given me a lot to think about.


I’ve been waiting for this summary! Thank you so much for doing this experiment and for sharing. I am forwarding this on!

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