Fat Loss Research Analysis

Q: What causes a plateau in fat loss?

The consumption of a hypocaloric diet and consequent fat loss lead to alterations in circulating levels of hormones that regulate hunger and satiety, which signals nutrient deprivation to the brain and results in increased hunger and food cravings as well as decreased satiety.[6] Alongside these physiological nudges to increase energy intake, total daily energy expenditure decreases with weight loss. This occurs for a variety of reasons, including reduced sympathetic nervous system activity, lower circulating levels of leptin and thyroid hormone, and increased skeletal muscle and mitochondrial efficiency. As a result of these changes, incremental decreases in energy intake are often needed over time to produce further fat loss.[7]

Q: Is it better to lose fat slowly or quickly?

Evidence from observational studies and randomized controlled trials suggests that losing weight quickly often leads to improved long-term weight and fat loss maintenance.[8][9] However, losing weight quickly may increase the risk of muscle and bone mineral density loss,[10][11][12] especially if weight loss occurs in the absence of a high-protein diet and resistance exercise. Therefore, athletes who need to maintain peak physical performance during a fat loss phase should pursue a slow rate of weight loss, whereas the average person can decide on their preferred rate of fat loss based on personal preferences.

Q: Does exercise type affect fat loss?

Interval training and moderate-intensity aerobic exercise can affect the body in different ways. But do these differences extend to fat loss?

Q: Does metabolism vary between two people?

Yes, metabolic rate (the amount of calories burnt a day) does vary between people. Most of the time, it isn't that much of a difference and isn't causative of obesity (where caloric intake and exercise are better predictors), but differences between people do tend to exist.

Q: Is there a “best diet” for fat loss?

Usually, in diet studies, weight loss differs little between diet groups but a lot within each group. In other words, individual results will vary. For example, in the Diet Intervention Examining The Factors Interacting with Treatment Success (DIETFITS) RCT, 600 participants were randomly assigned to either a low-fat or low-carb (non-keto) diet for 1 year, with intensive support from dietitians and research staff.[29] Here were the reported weight-loss averages: 5.3 kg (11.7 lb) in the low-fat group 6.0 kg (13.2 lb) in the low-carb group As you can see in the figure below, in which each bar represents the weight change of a single participant, individual changes varied widely in both groups: they ranged from -32 to +11 kg (-70 to +24 lb). 12-month weight change for each DIETFITS participant Adapted from Gardner et al. JAMA. 2018.[29] One reason for these differences is that some people stick to their diets while others don’t (a support network is very helpful for diet adherence), but another may be that some diets do work better for some people than for others, for reasons that aren’t yet completely understood. If there’s one takeaway to keep in mind after looking at all the evidence, it is that no one diet is inherently superior. Different diets work differently for different people, but the best fat-loss diet for a specific person will have at least two qualities: it’ll be hypocaloric (it’ll make adherents eat less than they burn) and sustainable (it’ll fit food preferences and lifestyle well enough that adherence is possible).

Mike Murray

Fat Loss

•Last Updated: November 20 2022

Fat loss occurs when more calories are expended than consumed.

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Mike Murray

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Morgan Pfiffner • Rob Stenstrom

Last Updated: November 20 2022

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Frequently asked questions

How does fat loss work?

There are three components of total daily energy expenditure: the thermic effect of food (i.e., the energy cost of the digestion, absorption, and storage of dietary macronutrients), basal metabolic rate, and physical activity, which can be subdivided into volitional exercise and nonexercise activity thermogenesis (i.e., the energy expended performing common daily activities such as standing, walking, and fidgeting). For fat loss to occur, energy intake must be less than energy expenditure.

What causes a plateau in fat loss?

Is it better to lose fat slowly or quickly?

How does exercise affect weight loss?

Does exercise type affect fat loss?

Does metabolism vary between two people?

How could diet affect fat loss?

There are no meaningful differences in fat loss between diets that vary in carbohydrate and fat content, as long as their protein and calorie content is equal.^[1]^[2]

Nonetheless, certain dietary factors can influence fat loss via their effects on energy expenditure, hunger, and satiety, and thus energy intake. These include ultraprocessed foods, which have been shown to increase ad libitum energy intake;^[3] protein, which has the highest thermic effect of food among the macronutrients, helps to preserve muscle during weight loss (and thus preserve basal metabolic rate), and may reduce hunger and prolong satiety;^[4] and fiber, which may also reduce hunger and prolong satiety.^[5]

Is there a “best diet” for fat loss?

Which supplements are of most interest for fat loss?

Supplements of interest for fat loss typically either increase total daily energy expenditure, suppress appetite, or increase the rate at which fatty acids are released from fat cells. The following are some of the most popular supplements related to fat loss:

Most supplements sold for fat loss are ineffective or there’s not enough evidence in humans to support their efficacy, and some can even be harmful. For example, yohimbine, ephedrine, and caffeine can all induce anxiety in some people.

Does Garcinia Cambogia help with weight loss?

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