Most attempts at weight loss fail in the long-term, and this includes even those that are effective in the short-term. The problem lies in the fact that all successful dietary interventions for weight loss have the same element in common: a caloric deficit. Regardless of which “diet” is used, the foods to be included or excluded, the timing and number of daily meals, or how delicious a low-calorie meal can be made, in the end weight loss is only achieved because the body is getting fewer calories than its metabolic rate demands. Research on dietary approaches like the ketogenic diet or time-restricted eating continue to show that while these are effective for weight loss, none of them are more effective than regular diets when the caloric reduction is equivalent. It seems the true determinant in any diet’s effectiveness is simply how long it can be adhered to, and the calories-in, calories-out dogma has repeatedly proven itself in scientific research by achieving the same steadily significant weight loss regardless of the method used, or the diet being studied. When choosing a weight loss diet, the only relevant consideration seems to be how willing a given individual is to remain on it.
Some people do find, on an individual level, that certain diets are easier for them to stay on than others, however the long-term results of caloric restriction are always the same: after some initial loss, a plateau followed by weight regain. This is not caused by failing to stay on the diet: even people using the popular GLP-1 mimetics for weight loss tend to experience plateaus while on these drugs, and of course weight gain is a notably common occurrence when the drugs are discontinued. Longitudinal studies on weight loss interventions of all types have revealed an invariable pattern that seems to hold regardless of the diet’s specifics: as long as there is some sort of caloric deficit, weight (as a combination of fat and muscle) is reliably lost at a steady, predictable rate for about three months, after which the weight loss plateaus, followed by a gradual regain of some but not all of the weight lost, culminating in a steady new weight within a year or so of starting that while lower than the initial weight, still falls short of the dieter’s goal. What’s remarkable is that during the regain phase, usually six to nine months after starting the diet, weight gain occurs despite the caloric deficit being maintained. Yes, there is hard scientific proof that it is possible, at a certain point even likely, to gain weight in a caloric deficit. How is this possible?
To understand this phenomenon, which seems to affect all dieters, the nuances of calories-in, calories-out must be reconciled. The body does lose weight according to the laws of physics, as in when fewer calories are going in than going out, a reduction in body weight is inevitable and guaranteed, but the point often forgotten is that to a large extent, the calories going in determine the calories going out. In other words, the body will adjust its metabolic rate depending on how much is being eaten, striving to maintain a given weight set point determined in part by genetics but primarily, by current hormone levels. In a state of health, eating a caloric surplus does not necessarily result in increased body fat. It may result instead in increased muscle mass, faster wound healing, better hair, skin, and nails, increased fertility, a stronger libido, or an improved immune system, all of which require calories to grow and maintain. It is also possible that eating more calories will simply cause one to generate more body heat and experience more energy throughout the day. Weight gain in the form of excess fat only happens when the metabolism fails to adjust itself equivalently to an increase in calories, and most healthy metabolisms can adjust themselves quite high.
Obviously, it is possible at some point to exceed this and eat more calories than the body is able to burn, but many people who carry excess fat are eating the same or even fewer calories than an average healthy, active person. The reason weight gain is possible in a caloric deficit is that after several weeks of being in a caloric deficit, the body responds by lowering its metabolism. This is achieved by reducing energy levels, generating less body heat, decreasing the rate of growth and turnover in a variety of organs and tissues, and especially, by decreasing muscle mass. While increased muscle mass is associated with longevity, muscle is a very energy demanding tissue and quite expensive in terms of daily calories to maintain. When calorie intake decreases, reducing muscle mass can lower the body’s caloric requirements and often accounts for much of the weight lost during dieting. If a calorie deficit persists, it is possible for the body to lower its metabolism far enough to re-create a modest surplus, and gain some weight back before establishing a new set point that can be maintained on the reduced caloric intake. This means the true long-term consequence of adopting a reduced calorie diet is somewhat less body fat, somewhat less muscle, and a permanently lowered metabolism that will cause weight regain if the diet is ever abandoned.
It is now believed that chronic attempts to lose weight through dieting can cause lasting harm to the body’s natural metabolism, effectively stalling continued efforts to lose weight. While this damage can be repaired, the best way to restore the body’s metabolism is unfortunately to eat more calories, which many dieters are afraid to do. It can potentially take months for the endocrine system to right itself from the stress of chronic undereating, and so if this strategy is employed, it is almost inevitable that some additional weight gain will occur. However, this two steps backward, three steps forward approach may be the best way to achieve a permanently healthy weight. It should be remembered that not all weight gain is bad: gaining muscle mass is considered beneficial to almost every dimension of health, and this typically requires a caloric surplus to achieve. Professional bodybuilders, who might be considered the world’s true experts at losing fat, will spend several months “bulking” to build both muscle and fat before cutting their calories to achieve their final form, and a big part of their secret to losing weight so successfully during this phase is the incredible amount of muscle they gained while bulking, as this muscle tissue dramatically boosts their resting metabolism.
It is not necessary to take muscle building to such an extreme to lose weight, and most people who engage in strength training as exercise will not need to worry about becoming bulky. In fact, people who have been dieting off and on are likely carrying less muscle than their bodies should, as losing muscle is one of the body’s main responses to living in a calorie deficit. Although counterintuitive, replacing chronic dieting with a caloric surplus and strength training may effectively reduce body fat without decreasing body weight, since muscle gained will typically weigh more than fat lost. Once a healthy metabolism has been restored, which may be evidenced by signs like improved energy and mood, higher body temperature, healthier skin and hair, improved libido, or more regular menstruation, it will become much easier to lose excess fat through reasonable caloric restriction. An especially useful way to monitor metabolism is to track reverse T3, a laboratory marker reflecting how much of the body’s thyroid hormone is being inactivated to save energy. As metabolism improves in response to adequate caloric intake, reverse T3 should go down.
One of the best secrets to keep a healthy metabolism while cutting calories is to use vinegar, and to a lesser extent medium chain triglycerides (MCTs). What these substances have in common is they both represent intermediates in the fat burning process. Most dietary fats are ingested as long-chain triglycerides, which when used for energy, get broken down into shorter chains and eventually, single acetate molecules. These combine with CoEnzyme A to form Acetyl CoA, the key precursor that powers the Kreb’s cycle in the mitochondria. The vast majority of calories burned as energy, regardless of their source, are first converted to Acetyl CoA, and vinegar (aka acetic acid) is essentially a source of pure acetate. The keto diet community has popularized MCTs, usually in the form of butter or coconut oil, as a way to provide rapid energy and stimulate fat burning, but vinegar has been used much longer to assist with weight loss and may prove to be even more effective. As a two-carbon molecule, acetic acid can be considered the shortest of short-chain fatty acids, half the size of the ketone supplement beta-hydroxybutyrate.
Exactly how these short-to-medium chain fats increase fat burning while decreasing fat storage is unknown, but it may involve tricking the body into grossly overestimating the amount of calories being eaten. It must be remembered that attempts to lose weight through calorie reduction often fail because they put the body into starvation mode. As soon as the body realizes that it is consistently failing to meet its caloric needs, it shifts into fat storage mode and if possible, produces a caloric surplus to store away as fat by simply lowering its metabolic rate. This is why it is possible to gain fat while on a diet. The best way to lose weight in the long-term is to increase metabolism, and the surest way to increase metabolism is to eat more.
There are some cases of people achieving weight loss by increasing their calorie consumption, although this is not common. Usually, this occurs when people who have been restricting calories for a long time on top of exercise increase their caloric intake to something appropriate for their activity levels. This brings them out of starvation mode and alters hormone levels in a way that promotes fat loss and muscle growth in response to exercise. Cortisol is the worst enemy of anyone trying to lose weight, and prolonged caloric restriction combined with exercise will often raise it. For most people however, weight loss is only possible with some degree of caloric restriction, ideally a modest caloric restriction that keeps the body out of starvation mode.
This is where MCTs and acetate can be useful: not only do they help trick the body into thinking it is not starving, they might actually trick it into thinking it’s eating more, thus boosting the metabolic rate in a caloric deficit instead of lowering it. Even though acetate is normally produced when the body burns fat, ingesting acetate in the form of vinegar seems to downregulate genes involved in fat storage and promote the burning of more fat, essentially a positive feedback mechanism. This is likely because whenever energy is highly available to the body, like after a large meal, acetate concentrations are high. Virtually all calories ingested are converted to acetate in the form of acetyl CoA, so normally one needs to eat fat and carbohydrate in large quantities, i.e. a high calorie meal, to generate significant elevations in acetate. These high concentrations, in turn, seem to increase metabolism in response to what is perceived to be a high energy availability. So by consuming acetate directly in the form of vinegar, which compared to fat and carbohydrate is extremely low in calories, the body will think it has eaten a large meal when in fact it has not, increasing metabolism and decreasing fat accumulation even in a caloric deficit. As long as this caloric deficit is modest, as in no more than 20% of maintenance calories (300-500 calories per day for most people), the result will be increased energy and further weight loss as opposed to starvation mode, weight loss plateau, muscle wasting and fat accumulation.
How much weight loss is actually possible with apple cider vinegar? When setting weight loss goals, it is important to be realistic and maintain a gradual reduction in body weight consistently. A Japanese study testing the effects of vinegar to combat obesity found that consuming 30 mls of apple cider vinegar in beverages per day resulted in about 4 lbs of fat loss over a 12 week period1, compared to no weight loss observed in the placebo group. This was achieved simply by consuming vinegar, with no increase in physical activity and actually eating slightly more calories than the placebo group. While not much, this still contributes a third of the 1 lb per week recommended as a healthy and sustainable rate of weight loss, without any focused exercise or severe caloric restriction (the subjects were all eating around 1800-1900 calories per day throughout the study). This suggests that while apple cider vinegar will not magically melt fat away at a rapid rate, it remains a valuable adjunct to support reasonable diet and exercise, with virtually no side effects.
As a natural weight loss aid, the best way to dose apple cider vinegar is to add 1 oz (30 mLs), roughly the quantity of a shot glass, to water or another healthy beverage that will be consumed throughout the day, or divide it into two doses by adding half an ounce per pint of liquid and consuming twice a day.
- Kondo T, Kishi M, Fushimi T, Ugajin S, Kaga T. Vinegar intake reduces body weight, body fat mass, and serum triglyceride levels in obese Japanese subjects. Biosci Biotechnol Biochem. 2009 Aug;73(8):1837-43. doi: 10.1271/bbb.90231. Epub 2009 Aug 7. PMID: 19661687. ↩︎