What are the challenges for weight gain for some people?

People who struggle to achieve a healthy weight are often impacted by underlying factors such as: 

• Reduced appetite: Certain disorders like dementia, anorexia and bulimia lead to aversion to foods. Diseases, medications and/or other psychological and physiological disorders can also reduce release or activation of appetite stimulating hormones that impact one’s ability to eat regularly. 
• Increased caloric demand: Conditions like cancer or prolonged illness increase physical stress on the body. The body undergoes catabolic changes causing a breakdown of muscle and tissue which can ultimately lead to weight loss and malnutrition.
• Inability to consume food: Certain cancers and conditions involving head and neck make chewing and swallowing difficult which impact one’s ability to eat and overall food intake.
• Intolerance to food: Chemotherapy induced nausea and vomiting or short gut syndrome which is a condition where your body is unable to absorb enough nutrients from food because you don’t have functioning small intestine.^[1]

What is malnutrition?

According to the World Health Organization (WHO), malnutrition includes undernutrition (wasting, stunting, underweight) and inadequate vitamins or minerals. It can also refer to deficiencies, excesses, or imbalances in a person’s intake of energy and/or nutrients.^[2]

Does supplemental nutrition work for weight gain?

Evidence shows that people who take supplemental nutrition have improved weight gain compared to those people who do not.^[3] There are several options for supplemental nutrition but in my experience as a physician, they don’t work equally for everyone. Let’s take a deeper dive on this topic.

What is listed on nutrition labels?

The most common nutritional supplements have high amount of protein with some carbohydrates, and usually low amounts of fat. The total calories on any nutritional label is the sum of calories from carbohydrates, protein and fat. Collectively they are known as macronutrients. Carbohydrates provide four calories per gram, protein provides four calories per gram, and fat provides nine calories per gram.

Is a calorie a calorie?

Protein, fat and carbohydrates go through different biochemical pathways to be digested. Some of these pathways are energy inefficient. This means it costs more calories for the body to digest one macronutrient over the other.^[4] For instance, as I mentioned protein contains four calories per gram, but many protein calories are lost as heat when they’re digested by the body. This is called the thermic effect of the food.^[5] On the contrary, very few calories are used by the body when fat is digested.

On average, up to 30% of calories from protein are used up for digesting protein compared to only 2% for fat and 7% for carbohydrates. For people who need every calorie they can get to support weight gain and combat malnutrition, losing 30% calories for digestion is simply too much.

Are high protein diets good to counter malnutrition?

When the body needs energy, it prefers nutrients like carbohydrates and fats as sources. When the body is not getting enough calories from nutrients or stored fats, due to not enough of them being consumed or when too many are being burned off through exercise, protein will used for energy. In the world of cancer nutrition there is a big push for a high calorie and high protein diet.  But it’s clear from the discussion above that adding each gram of protein to diet to replace fat or carbohydrate, will reduce total calories available to the body because dietary protein contributes little to energy (glucose) production.^[6] In people with malnutrition or who are at risk of malnutrition, protein intake without adequate fat and carbohydrate intake will cause amino acid catabolism leading to protein breakdown.

For example, a nutritional beverage containing 35g of protein and 250 total calories per serving will have 35 x 4 = 140 calories from protein alone. But not all of those 140 calories will be available to the body for energy. This is because 30% of the calories will be used as thermic effect to digest protein. The protein will be broken down into amino acids for muscle building and only a small amount will be used for glucose generation. As such, the beverage will only have 110 net calories that can be used as energy. Compared this to a beverage with 18 g of protein and 250 calories per serving. In this case only 72 calories will be from protein meaning 178 net calories will be available for the body.^[7][8]

Protein also happens to be a very filling macronutrient, which is why it’s popular for people trying to lose weight. But for those looking to put on weight, a high-protein diet can lead to early satiety. This can lead people to eat less and ultimately reduce caloric intake.

What is the ideal amount of daily protein intake?

Average daily protein requirement for adults vary from 0.8 g – 1.2 g per kg of bodyweight. The higher number of 1.2 g/kg is needed for people at risk of sarcopenia, which is a loss of muscle mass, strength and function. Therefore, the daily protein requirement for a 70 kg adult ranges from 56 g to 84 g per day.

Are all proteins equal?

The short answer is no. Proteins are made of amino acids and nine of them are considered essential. Essential amino acids can only be obtained from food. The other amino acids can be synthesized in the body as needed. Protein quality rating is based on digestibility and quantity of essential amino acids for providing the proteins in correct ratios for human consumption. The recommended Digestible Indispensable Amino Acid Score (DIAAS) scoring system compares all the protein sources for their quality.^[9]

Protein from sources, such as eggs, milk and quinoa, provide all nine essential amino acids in adequate amounts, and for this reason are considered “complete proteins.” Proteins from most plants, grains, nuts, seeds, and vegetables tend to be deficient in one or more of the essential amino acids and are called “incomplete proteins.”

Digestibility of protein is also an important factor related to protein quality. Many beans and legumes exhibit poor digestibility while soy, milk, eggs and meat products have higher digestibility. Overall, milk protein concentrate has the highest DIAAS rating.^[10]

Why are MCTs so popular?

MCTs refer to Medium chain triglycerides which are fatty acids (fats) with tail of 6, 8, 10 or 12 carbon atoms. There are four such MCTs namely caproic, caprylic, capric and lauric acid. Coconut oil and palm oil are among the richest sources of MCTs.^[11]

Fats are the richest source of calories for humans. Of all fats, only MCTs can passively diffuse from the gastrointestinal (GI) tract to portal system without need for bile salts for digestion.^[12] This is a critically relevant issue for any person with malabsorption due to gastrointestinal diseases or anorexia because MCTs do not need energy for absorption, utilization and storage. They act as an instant fuel for the body.

What is the difference between plant-based and animal sourced saturated fats?

Saturated fats are a contentious topic in nutritional science. For decades healthcare professionals, particularly cardiologists, asserted that the saturated fats increase cardiovascular disease risk because they increase low-density lipoproteins (LDL), commonly referred to as bad cholesterol. However, new research is showing that there are differences between plant-based and animal sourced saturated fats, and they may not be as bad as once thought.

For instance, a recent study comparing the impact of olive oil, butter and coconut oil on blood cholesterol levels showed that the use of olive oil lowered LDL but it did not increase the good cholesterol HDL while coconut oil increased the good cholesterol HDL significantly and while lowering LDL.^[13]

Many cultures that use coconut and palm oil exclusively for the cooking needs have shown excellent cardiovascular health. More research studies are being conducted to bring this important information into clinical practice.^[14]

What do you think of carbohydrates as source of energy?

Carbohydrates are essential source of energy. Development of modern agriculture has led to abundance of carbohydrates in our food chain. These carbohydrates are clinically classified into simple and complex. Complex carbohydrates contain longer chains of sugar molecules than simple carbohydrates. The body converts these sugar molecules into glucose, which it uses for energy.

Simple carbohydrates are quickly digested raising the blood sugar level. This is measured by Glycemic Index – the scale that measures how much and how fast the food raises blood sugar. This is a big issue in modern medicine because rapid rise in sugar leads to secretion of insulin and IGF-1. The frequent and rapid rise of these hormones increases risk of developing of type 2 diabetes,^[15] heart disease,^[16] as well as certain cancers.^[17][18] Therefore, it is beneficial to your long-term health to limit foods with added sugars and with high glycemic index ingredients such as maltodextrin, a commonly used sweetener. Ingredients such as maltodextrin may not be listed as an “added sugar” even though it has a higher glycemic index than sugar!

Are you concerned about impurities in nutritional products?

Absolutely. Processed foods tend to have impurities sneaking into them during manufacturing.  Lead, cadmium and arsenic are found in protein supplements and plant-based proteins fare worse. A recent study found that “Overall, the products made from sources of plant protein such as soy or hemp fared worse than those made from whey (milk) or egg, containing on average twice as much lead and measurably higher amounts of other contaminants.”^[19]

Plant-based proteins may have higher contamination levels because the plants are especially prone to absorbing heavy metals from soil. Brown rice syrup has also been found to have high arsenic level.^[20]

References:

1. Short bowel syndrome, https://www.mayoclinic.org/diseases-conditions/short-bowel-syndrome/symptoms-causes/syc-20355091
2. Malnutrition, https://www.who.int/news-room/fact-sheets/detail/malnutrition
3. Cholesterol, coconuts, and diet on Polynesian atolls: a natural experiment: the Pukapuka and Tokelau island studies, https://www.ncbi.nlm.nih.gov/pubmed/7270479
4. “A calorie is a calorie” violates the second law of thermodynamics, Richard D Feinman and Eugene J Fine, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC506782/
5. Measuring the Thermic Effect of Food, https://pubmed.ncbi.nlm.nih.gov/8561055/
6. Dietary Proteins Contribute Little to Glucose Production, Even Under Optimal Gluconeogenic Conditions in Healthy Humans, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3636601/
7. Postprandial thermogenesis is increased 100% on a high-protein, low-fat diet versus a high-carbohydrate, low-fat diet in healthy, young women, https://www.ncbi.nlm.nih.gov/pubmed/11838888
8. Presence or absence of carbohydrates and the proportion of fat in a high-protein diet affect appetite suppression but not energy expenditure in normal-weight human subjects fed in energy balance, https://www.ncbi.nlm.nih.gov/pubmed/20565999
9. Protein quality as determined by the Digestible Indispensable Amino Acid Score: evaluation of factors underlying the calculation, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6322793/
10. DIAAS for foods, https://www.todaysdietitian.com/newarchives/0217p26.shtml
11. Impact of coconut oil consumption on cardiovascular health: a systematic review and meta-analysis, https://www.ncbi.nlm.nih.gov/pubmed/31769848
12. Medium Chain Triglycerides and Structured Lipid, http://220.194.44.18/liwen/documents/20130226144222939.pdf
13. Randomised trial of coconut oil, olive oil or butter on blood lipids and other cardiovascular risk factors in healthy men and women, https://www.ncbi.nlm.nih.gov/pubmed/29511019
14. Cholesterol, coconuts, and diet on Polynesian atolls: a natural experiment: the Pukapuka and Tokelau island studies, https://www.ncbi.nlm.nih.gov/pubmed/7270479
15. Whole grain, bran, and germ intake and risk of type 2 diabetes: a prospective cohort study and systematic review, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1952203/
16. High dietary glycemic load and glycemic index increase risk of cardiovascular disease among middle-aged women: a population-based follow-up study, https://pubmed.ncbi.nlm.nih.gov/17601539/
17. Dietary glycemic index, glycemic load, and cancer risk: results from the EPIC-Italy study, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5575161/
18. Over-stimulation of insulin/IGF-1 signaling by western diet may promote diseases, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3141390/
19. Arsenic, Lead Found in Popular Protein Supplements, https://www.consumerreports.org/dietary-supplements/heavy-metals-in-protein-supplements/
20. Brown rice syrup puts arsenic in organic foods, https://www.foodsafetynews.com/2012/02/brown-rice-syrup-puts-arsenic-in-those-organics/