The ketogenic diet, popularly known as keto Diet has its advantages. However, most of the studies or observations were with those patients who did not have bariatric surgery or any other major change in the gastrointestinal tract. It remains a concern whether the Keto diet should be advised after bariatric surgery. There is no data at present to recommend keto diet after bariatric surgery.

Here are some concerns which come to my mind:

Bariatric surgery does induce volume restriction and the principal is to maintain that restriction for a longer period. It may not be easy to achieve the composition like the keto diet, for example, 70 per cent calories from fat, without compromising on the necessary elements like protein, fibre and minerals. At the same time, absorption of those calories is not certain in bypass procedures which may defy the mechanism of the diet. On the other hand, in some individuals or after procedures like sleeve gastrectomy or at times even bypass, it is likely that the total calories may even exceed than the usual bariatric norms.

The basic mechanism of the keto diet is the preferential use of fat as energy by inducing ketosis. There is no evidence to know whether this state of ketosis can be induced in the same manner after bariatric surgery, as if in a normal individual. The change in hormones after bariatric surgery and subsequent change in metabolism induces weight loss, rather fat loss.

Even though bypass procedures have fat malabsorption, one does not know whether we should offer this challenge of excess fat in these patients. It may induce rapid transit, frequency of stools, loose motions and malodourous stools in some procedures. It is not known whether dumping would be frequent and whether frequent dumping would be favourable. This different phenomenon may define a different ‘keto flu’ like syndrome in these patients after keto diet.

There would certainly a change in gut microbiota induced by a keto-type diet rich in fat and low in fibre. Whether it would lead to adaptation for better fat absorption is still not known. If it does, it may compromise the result of the procedure over the long term, especially with the question whether the keto-type of diet would be sustainable over the long term. In my experience, a few of the patients who attempted keto diet, succeeded in losing weight for a short period and eventually all 32 of them became candidates for revision in the next two to three years.

It appears that Keto-type of diet after bariatric surgery will aggravate protein, mineral and vitamin deficiency. Guidelines for these supplements may need to be modified while the individual is on a keto diet and will need further studies.

Keto diet may have to be modified, (if at all it needs to be attempted in a patient after bariatric surgery), studied with reference to efficacy, absorption, ketone levels, deficiencies, hormonal changes, impact on NASH, etc. Studies with longer follow up are needed before recommending it to a patient after bariatric surgery.

The keto diet does not work well after bariatric surgery for the following reasons:

• The high-fat content of the keto diet (70% of calories) does not allow for the consumption of adequate protein or carbohydrates.
• A high-fat diet may lead to fatty diarrhoea (steatorrhea) and reduced absorption of nutrients because food tends to travel faster through the intestinal tract after bariatric surgery. There is a risk for nutritional deficiencies after bariatric surgery; severely limiting specific food groups (whole grains, fruits, and many vegetables) only increases the chance that deficiencies will occur.
• Fat contains 9 calories per gram, while carbohydrates and protein contain 4 calories per gram—making fat a very concentrated source of calories. It is very easy to exceed calorie needs when consuming a high fat, low carb diet. Calorie intake 1 year or longer after bariatric surgery typically ranges from 800–1100 for women and 1000-1500 for men per day.
• The keto diet is low in fibre. This increases the risk of constipation, which can be a concern after weight loss surgery. Fibre may also reduce the risk of developing various conditions, including heart disease, diabetes, and diverticular disease.

Although the keto diet does show some short-term promising results for weight loss, it is not a good diet strategy after bariatric surgery. A lifestyle that supports a healthy weight after bariatric surgery is something that can be followed life-long, with protein at the centre of the diet. The keto diet with its extremely high-fat content, very low carb content, exclusion of grains and fruit, and low fibre content are potential concerns for overall health. This is even more of a concern after bariatric surgery when portions are limited and nutritional deficiencies are a risk.

Hedonic hunger is the pleasure of eating in the absence of any deficit. Even smells, visuals, or thought of food may stimulate hedonic hunger. High-calorie food and sugars have a higher potential for stimulating hedonic hunger. Hedonistic eating can easily override the body’s protective homeostatic mechanisms to control eating.

Certain individuals have an affinity for certain foods and there is wide variability between individuals. Even genetics is known to have a role in this.

Various other factors influence eating and they are the composition of food, palatability and these could further be different for people.

What happens in the body when you start eating less?

As you start eating less, you start losing weight. The body’s physiology always tries to get the weight back, by increasing the hunger hormone, called Ghrelin. For some, it is exceedingly difficult to fight against the craving or hunger-induced internally by the hormones. This happens more in those who have crossed a certain stage of obesity or have many failed attempts.

Excess craving, excess hunger, an increase in the amount of food consumed at one time or over a period suggests some hormonal or metabolic imbalance. It could be induced by genetic susceptibility, some medications, stress, depression, or even a hormonal imbalance in the body. Such individuals need help from an obesity expert.

Keeping all the above in mind, let us understand how one can stop overeating.

Simple tips:

1. The smaller size of the plate and the smaller size of the serving.

This is to give a signal to your brain that your plate is full.

2. Drink a lot of water for the whole day.

Water is the best medicine without any side effects(those with kidney disease need to follow their nephrologists’ advice).

3. Eat more proteins or consume food with a rich source of protein as the main component of the meal.

4. Consume more fiber in your diet. This will help improve your satiety.

5. Have smaller bites or cut foodstuff into smaller pieces. Eat slowly and chew your food till it is converted into a paste. This will make your brain feel that you are eating more, and some compensatory changes can be overruled.

6. Eat on time and follow a certain schedule which is feasible.

7. Follow your circadian rhythm for food and sleep.
Circadian rhythm is a physiological, biological, and behavioural cycle that has an impact on mentation, metabolism, and hunger. Sleeping at night is an example of light-related circadian rhythm and maintaining these is important for better health.

8. Make your meal colourful, by addition of vegetables and fruits. This improves your hedonic affection towards healthier food, and these are rich in nutrients, antioxidants, and vitamins. Consuming adequate quantity and quality of nutrients prevents deficiencies and will further reduce overeating induced by the body in demand for certain nutrients.

9. Concentrate on your meal while eating. Avoid the use of mobile while eating and avoid eating while watching TV or working on a computer.
Diverting your brain away from your food or eating reduces your brain’s capacity to identify that you are full. This results in overeating.

10.Mindful eating: Mindfulness is a philosophy to be used while eating. Identify your external food cues. Eat for survival and better health and not only for pleasure.

11. Add bulk to your food using items rich in protein, fiber, and are low in calories. This can be done as per individual choices. The intention should be to lower the total intake of calories.

12. Do not stock sweets, junk food, or high-calorie food. If your mind knows that it is stocked, your hedonic hunger drives may get stimulated.
If at all you have some of it stocked, try avoiding the smell or visual as a food cue and keep it stored away from the dining area in an opaque and airtight container.

13. You can use some meal replacements that are low calorie, high protein, and high fiber. These can be used initially as a meal replacement or as an alternative to a snack.

14. Regular exercise is important and a combination of low resistance and high resistance exercise at least for 20 to 30 minutes a day, or at least three times a week preserves and improves your lean body mass/muscle mass while you are eating less. This in combination with a healthy and balanced diet makes it a healthy weight loss.

15. Stress management is equally important to stop overeating. There are various ways to reduce stress and one should opt for an appropriate option or a combination of options.

Caution:

A stitch in time saves nine!

Start early and attempt as much.

If you are not able to achieve optimal success, you may need help with some pharmacotherapeutic agents after a thorough evaluation and investigation.

Those with morbid obesity or associated disorders may find it difficult to achieve success with these tips. It is not their fault nor a lack of motivation. For them, it is a disease of hormones and metabolism beyond their capacity to fight.

Bariatric and metabolic surgery is the only scientifically proven method for long term weight loss and success for these unfortunate ones. And after the surgery and correction of hunger hormones and other hormones governing metabolism, it is so easy and enjoyable for them to follow all these tips to maintain success for years.