FEED CONVERSION RATIO: A Simple Fact of Gaining

What is the FEED CONVERSION RATIO, and does it have any relevance to hard-gainers? Yes, so tuck in for a long read. You need to know that foods you eat are not 100% utilized. You do not digest everything you eat. Some of the calories you eat slip out the other end. Digestion is never 100% efficient. How can we know this? Well, pardon the "yuck"-factor, but if you've ever seen corn or peas in your stool, you know it. If lactose makes you gassy, that attests to this. The very fact that 30% of nuts you eat are eliminated, if not well-chewed, is also proof of this. THIS is why I often say, "You're not a hard-gainer, you're a hard-digester". This is often the result of mal-absorption.

See, it's not how much you can eat, it's how much you can digest. And some people are just "not as good" at digestion. This isn't your "metabolism", this is poor food utilization. Additional factors contribute to our ability to process the foods we eat. Food calories can be lost in other ways, to other physiological processes. But we want to maximize the conversion of our calories into weight gain, correct? This is why I wanted to take a moment to have a closer look at this concept of Feed Conversion Ratio. Where does this ratio come from? And does it have any relevance to a hardgainer simply trying to put on good weight?

This Feed Conversion Ratio comes from the livestock industry. These are the folks who fatten up pigs and cattle, to get them to market. These are the people who are highly invested in getting their animals quickly to a certain weight. The animal's gains are literally the farmer's profits. And it would be ideal if each pound of feed produced a pound of meat. But it's nowhere close to this number! The ratio averages 3:1 in the example of a pig. It takes roughly 3 pounds of feed to yield 1 pound of weight. As an example, you might feed 665 pounds of feed to a pig in the weeks it weighs between 40 pounds and 280 pounds. You would calculate the ratio as "665 pounds of feed divided by 240 pounds of weight gain for a score of 2.77". You could thus say "the Feed Conversion Ratio is 2.77:1" in this instance.

Now, every animal has a different score for feeding efficiency. For beef cattle, FCR calculated on live weight gain of 4.5–7.5 was in the normal range with an FCR above 6 being typical. Some data for sheep illustrate variations in FCR. An FCR (kg feed dry matter intake per kg live mass gain) for lambs is often in the range of about 4 to 5 on high-concentrate rations. As of 2011 in the US, broiler chickens has an FCR of 1.6 based on body weight gain, and mature in 39 days. A lower first number in the ratio is desirable, as less feed is required to yield the same amount of meat.

If it requires 6 pounds of feed to make each pound of beef, versus 3 pounds of feed to produce a pound of pork, versus only 1.6 pounds of feed to grow a pound of chicken, then it's obvious that chicken is more economic in the simple sense that you spend less on animal food to grow the animal for market sale. But even on a species-by-species basis, there is variance within the species breed-by-breed. Sure, the average for a pig is 3:1. But some breeds of pigs might require 3.5 pounds of feed, on average, to gain a pound of weight, while another breed of pig only needs 2.6 pounds of feed to gain that same pound of pork. The latter breed gains weight & muscle with less food.

By this logic, we must extrapolate a conclusion that even among human people, there is not an equal ability to convert food into weight with an identical efficiency. We cannot assume that everyone responds to food (calories) in an identical manner. Is this due to "metabolism"? Largely, NO. Studies in metabolic wards have confirmed that although some people do have higher basal metabolic rates (resting metabolism), the effect is very slight. It's on the order of about 150-200 calories. Of people with identical height, weight, and body composition, one person might burn 150 more calories in a day. That's really not a lot. So what's going on with hardgainers who swear up & down that they're eating so much more than everyone else? Is this really happening?

First, can we even find a Feed Conversion Ratio for humans? It doubtlessly exists. But that would be beyond the scope of this article. Moreover, it would be highly impractical as well as unethical. For starters, we aren't eating an iso-caloric pelletized food kibble for all of our food intake needs. We also aren't looking at basic-rate growth from infancy-to-adulthood based on per-pound of feed; we're looking in the particular context of weight gain in response to resistance-training hypertrophy. But we don't need to know a rate of efficiency. It's enough to know that the absorption & assimilation of food is variable. And it's affected by other variables, besides enzymatic digestion.

Environment and Temperature can have a big effect on appetite. A pig’s environment can affect its food consumption and conversion. The ambient temperature of the pen must be kept in the thermo-neutral range or it will have a negative influence on a pig’s appetite. Pigs that are cold will eat more feed. Pigs that are hot will eat less. High humidity can also reduce appetite, as can poor ventilation. As a human goes, I can personally attest that I don't want to eat as much when it's too warm, or too stuffy. If "poor appetite" is a complaint of yours, this could be one explanation: Your environment is simply too warm for you to get the signal to eat for warmth! A meal should make you warm, due in part to the thermic effect of food. Digesting food requires your body to ramp up, and if you're already warm, hunger may be blunted or muted altogether. And conversely, if it's far too cold, animals will eat more, but also burn more, for heat. Some calories will be lost to heat, when they could have been used for growth.

Are we pigs in a pen being raised for food? Certainly not. But is it unreasonable to assume ambient temperatures play a factor in appetite, as well as metabolism, in the human? Burning body fat for heat is an element of "calories out", and it's the largest component of non-exercise energy expenditure. Are you guilty of insisting on wearing a T-shirt in the house during Winter, instead of bundling up a little bit indoors? Not-eating when too warm can impair appetite some of the time, coupled with over-burning when exposed to cooler temperatures and needlessly burning calories for heat another part of the time, can both contribute to impaired weight gain for two different reasons.

Animal Stress also factors into appetite strength. If the density of pigs in the pen is too high, they will experience stress which results in eating less. I'm aware that only so many extrapolations can be made from our pig-farming corollary here, but this also bears legitimacy: People, too, often eat less in times of stress (some are known to eat more, but that's not our demographic). Common stress can play a big role in appetite impairment. So it goes without saying, you might be experiencing stressors in your life, even if unbeknownst to you. Making time to relax before eating a meal might help unlock some of that. A simple 10-minute walk to clear your head and get some fresh air can work wonders in giving your appetite the boost it needs. Mindfulness & meditation may also promote de-stressing.

To shift back to another topic, there is also an effect that results in poor food utilization, which I call the "Novel Meal Phenomenon". This is the result of an excessively varied diet, to which the body does not have sufficient time to adapt. This is something you can observe if you've ever had a dog: They acclimatize to their particular brand of dog food and this produces a firm healthy stool. But if you switch food brands suddenly, they'll typically have loose stools for the next couple of days while they adjust to the different macro composition and nutritional profile of the food. This is why it is recommended to mix a little of the new food with the food the dog is already accustomed to, in order to gradually transition the dog to the new food over a couple of weeks, rather than switching all at once. This gives your canine companion some time to re-calibrate its own production of digestive enzymes.

When you are exposed to many of the same foods on a regular basis, your body starts to anticipate them and becomes more efficient at processing them. And although there's still not 100% conversion to usable calories for energy, repair, and growth, more of the total food value is harnessed. If you are often troubled by loose and sloppy bowel movements, it might be due to the novel foods that you've eaten; you've thrown your gut biome a curve-ball. (It's not that those foods are necessarily "bad", and had you eaten only those meals, you likewise would have adapted to them over time, by modifying your endogenous enzyme profile). It's a demonstrable fact many people are enzyme-deficient. Some have a poor stomach pH, and will not absorb foods the same way as someone else can. But this is easily remedied. There's a limit to what enzymes you can make, but not to which enzymes you can take.

This is why I'm continually recommending either supplemental digestive enzymes, or enzyme-rich food sources, or both, if you're trying to gain meaningful mass. If you provide digestive support, you will convert more of the foods you eat into mass. If you're hell-bent on running GOMAD (Gallon of Milk a Day), but milk always makes you gassy and crampy, Dairy is probably not a desirable candidate food. (Though if you're determined to attempt it, it would behoove you to either drink only lactose-free milk, or take a lactase-containing digestive supplement alongside it each time. What sense is there throwing a food into the mix, if you're unable to process a component of the food?) Additionally, there is value in probiotics for gut biome support. 

Simply lowering the stomach pH (making it more acidic) can also help. Eating more citrus fruits, berries, and fibrous greens is another tactic to improve digestion. You'll be getting necessary vitamin C, valuable polyphenols and other micro-nutrients, but the biggest value is in digestive support. They also contain fermentable carbs that nourish the gut biome. These are the intestinal bacteria that help digest your other foods. Some of the things you cannot digest, your gut flora will digest for you. Then, you digest the gut flora, and the circle is complete. A thriving gut biome is absolutely necessary not only for raw digestion, but for overall health. At times, I've also kept a bottle of lemon juice in the fridge (not lemonade, but un-sugared, un-watered-down pure lemon juice), of which I drink a Tablespoon-sized shot after a large and bloating meal; it greatly assists in breaking down foods.

Further, this is also why I recommend sticking to 3 or 4 of the same meals which comprise 90% of your bulking diet. Find a handful of meals you don't mind eating all the time. Beef & rice, chicken & pasta, chili & cornbread, beef & bean burritos, tuna sandwiches, whatever your jam is. Rotating through the same small selection of meals will make food prep easier, it will make calorie tracking easier, and it ultimately helps take the guesswork out of what to eat next when it's time to eat again. But equally important, your delicate gut biome will become more adept and adroit and maximizing food absorption. More of the calories you consume will convert into usable energy, primarily in the form of meaningful weight gain. Try thinking of your stomach & intestines as a living creature you have to take care of, like an exotic pet. And when you provide for all the needs of this magical animal, it returns the favor by nourishing and growing YOUR body in return. When it is happy and healthy, it will bestow great gains upon you!

EAT With Purpose! We're All Gonna Make It!